You can help your kitten(s):
Since putting this information on the web, I have had numerous enquiries from breeders who have had kittens develop this condition. I’m afraid I don’t have any perfect answers, but I can pass on what feedback I’ve had regarding results and possible causes, and the results of my own observations.
Nutritional support and drugs
This is essential – it is surprising (and worrying) how many vets do not seem to be able to diagnose this condition, nor know anything about it, despite the fact that it is very widespread, and relatively well-known in the breeding community. A large number of kittens with FCKS are mis-diagnosed as having pectus excavatum, or the vet simply does not notice a thoracic or spinal deformity. If this is the case with your vet please take copies of the literature to him/her, and ensure that your research is sufficient to help you support and treat your kitten if your vet is unable to help. Please read the section about diagnosis and recognising this condition (What is FCK or FCKS?) if you haven’t done so already. Remember: FCKS is caused by collapsed lungs. It is not a muscular spasm.
I recently observed a kitten with a very mild case of FCKS: his weight gain never stalled, and he was not flat all the time (this is very unusual: most kittens go flat and stay flat). The important point to note was that he ONLY WHEN FLAT WHEN HE WAS SUCKLING. It was clear that whatever he did with his breathing or body while suckling, this caused him to go quite noticeably flat. In this case we believed that the kitten had something wrong with his diaphragm, which is used to help in sucking, and this caused his breathing to be affected.
I encouraged this kitten to lie on his side between feeds, which made his chest go to a normal shape, and if he stayed on his side while feeding he did not go as flat as if he was lying tummy-down. This may explain why some kittens with FCKS improve if they are hand-supplemented: if suckling makes them flatten more, then suckling less means less stress on the lungs, so they do not collapse so much or so quickly, and the ribcage is able to keep the lungs from deflating as badly as they might. Some forms (NOT ALL) of FCKS may therefore be exacerbated by suckling, and possibly taking a kitten away from its mother and hand-feeding it may allow it to recover, but only if the hand-feeding means the kitten does not have to suck to get the milk. Since then I have noticed that a small proportion of kittens go slightly flat when suckling, but are not flat when resting.
I am grateful to Dr Ray Wigley, who has written a short paper explaining one reason why kittens may suffer from lung collapse at 3 days of age.Please note that this is only a working hypothesis and only relevant to FCKs which happens very soon after birth (within 3 days).
Flattening takes place over the course of 2-3 hours. It happens gradually, so the kitten is not normal one minute and flat the next. Observation of the condition developing saw a large healthy kitten with no discernible symptoms become almost completely flat over the course of 2 hours, while it was sleeping – no doubt caused by progressive atelectasis. Now that I know a little more about atelectasis I realise that I should have immediately wakened the kitten and encouraged it to cry and expand its lungs with exercise. I checked the thorax by feel: as each breath drew the ribcage in slightly more, the development of the condition was very clear. Although light pressure was applied by hand to discourage the ribcage from adopting the unnatural shape the development of the condition was not arrested, but stabilised by itself.
Once the kitten reached a state where the ribcage was horizontal across the underside, the condition ceased to worsen, and the kitten stabilised. The kitten showed no obvious signs of distress during this process, woke and fed normally, and otherwise behaved as the other kittens in the litter did.
FCKS does not leave the kitten with the ribcage in a fixed position. The thorax is flexing all the time, and the degree of flatness changes during each inhale-exhale breathing cycle. When the kitten breathes in, the sides move outwards and the underside comes up towards the spine, increasing the flatness. On exhalation the sides collapse inwards, and the underside of the chest moves downwards away from the spine. Thus when the lungs are supposed to be full, the condition is noticeably worse. The chest goes flat because the lungs are not inflating properly – we do not yet know what causes the lungs to collapse, but it is evidently NOT caused by the chest: the chest collapses because the lungs are not inflating. OXYGEN WILL NOT HELP this condition, and indeed is likely to worsen the problem. You should only use oxygen if the kitten is in distress to support it on the way to the vet to be put to sleep.
NUTRITIONAL SUPPORT AND DRUGS
It is important to get your kitten to the vet as soon as possible once it starts to go flat – within hours if you can. You need to ask your vet to administer steroids to speed up the kittens’ development and an antibiotic that will support the immune system against the immune-depressant effects of the steroid. In the UK the steroid used is Dexamethasone, and the antibiotic is Amoxycillin. You can help your vet by weighing the kitten carefully just before you visit, and try to get the weight in grams rather than ounces so that s/he can calculate the dosage. The antibiotic will also help to combat any infection that might be causing the flattening. If you can persuade your vet also to deliver nebulized surfactant this may help if the cause is lack of surfactant, but this needs to be done within 3-4 days from birth to have any effect.
One thing that most breeders recommend is to supplement-feed affected kittens with a very high-quality kitten milk supplement, even if they seem to be feeding well from the mother. Nutritional maintenance is crucial in survival. If a kitten refuses to suckle or be hand fed, then tube-feeding is necessary. One breeder observed that FCK kittens seem to use far more energy than normal ones just to keep up, so it is reasonable to expect that the kitten would need supplementing. Often the first thing that alerts you to a problem is that the kitten stops putting on weight, so supplementing is a natural step to counter that stalling in growth and development. I am convinced however that a lot of these kittens stop gaining weight because they get colicy: having difficulty in breathing may cause them to swallow more air than normal when suckling, and this makes them feel full when they are not (so they stop feeding), and also can cause colicy wind which makes feeding painful. It may also make the stomach push against the diaphragm, contributing to the difficulty in breathing and exacerbating the lung collapse. I had one kitten whose weight stalled, but if a normal kitten had a weight stall I would always give it a drop or two of liquid paraffin to ease colic, and the weight would immediately pick up. I did this with my FCKS kitten and he immediately gained weight again, catching up what he had missed while he was flat. If I didn’t dose him with liquid paraffin his weight stalled again, but as long as he got a single dose of one or two drops from an eyedropper every day (sometimes two doses if he looked miserable) then he continued to gain weight, and his recovery was much faster than with kittens not given this support. I did not supplement feed him as he refused it and became distressed. Another kitten with this problem stalled without supplement feeding and had to be tube fed. He immediately picked up and improved, though he never accepted normal bottle feeding and had to be tube-fed until he was old enough to start weaning.
Kittens treated with drugs and with liquid paraffin seem to recover much faster than kittens who are not treated: as little as 6 days as opposed to 6 weeks to 6 months, so it is well worth pursuing this course of treatment.
For supplement feeding Cimicat doesn’t seem to be much use as it’s not very rich, and I would only recommend KMR which is an excellent creamy-rich milk substitute, and has saved the lives of countless kittens who did not thrive on Cimicat, regardless of whether they had FCK syndrome. In the UK the supplier is KRUUSE UK Ltd, tel 01977 681523. They have always been very helpful and will despatch the powder to you the same day if they can. However Kruuse are now only able to sell on a non-retail basis, so you would have to make a bulk order or buy through your vet. I’m afraid it’s not cheap! Your vet will charge the retail price, which is about twice the price from Kruuse, but you don’t have to buy in bulk. You can also get it from CANINE CHEMISTS Tel: 0870 225 4777 (thanks to Doris for sending me the details). In the US, KMR is available at the chain PetSmart. The US distributor is PetAg Inc., 255 Keyes Avenue, Hampshire, IL., 60140; 1-800-323-0877 (Many thanks to Don for this information). Once opened you can keep the powder for a reasonable period in the freezer, so you don’t have to throw it away when you stop using it, but it does go off eventually, even if unopened.
The other alternative is evaporated milk (brand name Carnation in the UK) diluted with water (about 1 part Carnation to 3 parts water) with a raw egg yolk beaten in (as long as you are happy that your egg supply is free from Salmonella). This is VERY nutritious if you can’t get KMR, Cimicat or the new Royal Canin kitten milk powder. I would supplement often to make sure the kitten is getting enough nutrition. The exercise of struggling against you (at first) and of suckling from a syringe may also help the lung development, though as I have noted, suckling can increase flatness. Struggling will also tire the kitten however, and you may have to abandon hand-feeding if it is counter-productive because of exhausting the kitten.
The following information came from Jane Turner in Canada, a breeder of Maine Coons: “I have had in the past the odd FCK kitten in a litter, but have never had a whole litter affected, so I’m not sure if it is genetic or not. I now supplement most of my queens with Taurine as routine, I was using 500 mg a day. One queen I had not supplemented, as she had never had an FCK kitten in her previous 2 litters, had a kitten go flat chested at 6 days old, just suddenly, so we supplemented her straight away with a dose of 1000 mg Taurine once a day; within 2 days the kitten who was completely flat on the bottom was coming out of it and by 5 days you would not have known he had ever been flat. When he went flat his breathing was definitely faster and he didn’t gain much weight for a couple of days, but he was still suckling and would not take KMR from us. His mum had lots of milk so we left him alone, now he is as large as his litter mates and feels perfectly normal when you pick him up; he is just over 4 weeks old and is eating solid food now (he was the first one to start eating!) … I have never used such a high dose before, but when I have put queens on Taurine the kittens seem to survive and return to normal within a couple of weeks, always by the time they are 8 weeks old you can’t tell they had anything wrong with them: even my vet couldn’t feel anything wrong when they have been vaccinated. We moved from England to Canada nearly 2 years ago, and I had to buy a different brand of Taurine this time, I think it was better: it was capsules with a powder in it, rather than a solid tablet, so any difficult-to-pill queens just had it on their wet food no problem.
If you would like to contact this breeder you can reach her by e-mail: jane[at]dotcommainecoons.com
I used Taurine with a queen with a single flat kitten (who went flat at 6 days), together with steroid/antibiotic/liquid paraffin, and he recovered very quickly.
Taurine is available in the UK from Holland & Barrett health food chain, and I found that I could crush up the tablets and mix it with the queen’s raw rabbit and she ate it without trouble.
The more you can understand the condition of your kitten, the better you can help it, so spend time with the kitten observing the condition and how it affects the kitten, what makes it worse, and what makes it better. You can observe by watching and by feeling the kitten while it is lying at rest, feeding or moving around.
Flattening occurrs at any time from 3-10 days after birth, but is more likely to appear sooner than later. Although we do not know absolutely what causes the lungs to collapse, we do know that there can be many causes. If the cause is respiratory disease the kitten exhibits abnormal rapid breathing BEFORE the ribcage flattens, and the effort of drawing breath in causes the ribcage to flatten. Note,: not all kittens who get pneumonia go flat, and not all flat kittens have pneumonia.
For this reason putting a kitten with FCKS on a broad-spectrum antibiotic as soon as the condition is noticed is advisable, since it will help if the kitten has pneumonia.
Some vets believe that the condition is due to a vitamin deficiency, and the most commonly used vitamin supplement for kittens is Abidec. This is a liquid vitamin supplement for babies and toddlers available from an ordinary chemist (unfortunately it tastes disgusting). If in doubt ask your vet. Remember that these kittens are always very young and small, so any treatment is very difficult. You only need one drop of Abidec per kitten, so don’t end up squirting it down their throats so that they choke. I have used Nutri-drops in a very mild case, and that seemed to help – Nutri-drops is mainly glucose and vitamin A, and a cocktail of other vitamins. It will give a kitten energy to suckle more, which is helpful if your kitten fights against a hand-fed milk supplement. If you know of sources of supply for this supplement outside the UK, please let me know so that I can put the information here.
The problem is how to re-inflate the lungs. In humans reinflating collapsed lungs is done over a long period using positive pressure from a mask over the face. This cannot (obviously) be done with a kitten.
Because the thorax is flexible, it can be pushed into the correct position by squeezing the kitten’s sides. DON’T expect the ribcage to round out immediately and DO NOT on any account attempt to force it, or you could kill the kitten. The best way of doing this is not to apply continuous pressure, but to apply greater pressure on exhalation when the more natural position is reached, and gentler pressure when the kitten is inhaling and the flattening is most extreme so that you do not prevent the kitten from inhaling. The more active the kitten is, the more extreme the position of the ribcage, so it is better to keep the kitten calm and quiet, particularly during massage. Most kittens, far from being distressed by this, seem to enjoy it, and you can judge how much pressure to apply by the reaction of the kitten. A good time to massage is during feeding. This has two purposes: the kitten is relaxed, so the condition is less extreme; the activity ensures the kitten remains alert and suckling when it might otherwise fall asleep, so it suckles for longer – it may also help the kitten not to swallow so much air. Since kittens with FCKS use more energy than normal kittens, encouraging them to feed longer and waking them for extra feeds is highly desirable.
You may have to utilise different types of massage. The first and most effective is simply to put thumb and fingers on either side of the body and press on the ridge on the sides. Do not apply continuous pressure, but change the pressure in time with the breathing. For quite a lot of affected kittens this seems to cause them no distress, but if a kitten fights against this and cries out, a different method is necessary, which involves again using the thumb and fingers on either side of the body, but instead of squeezing, you rub the ribcage gently in a downward position from the spine down, applying inward pressure as you do so, just down as far as the angle made by the flattened ribs. You have to do this in time with the natural in-out movement caused by breathing. This seems to be more comfortable.
Massage should be maintained for at least as long as a kitten is feeding, and longer if possible. The longer you massage, and the more frequently it is done, the more help it seems to be to the kitten. After massage the chest is noticeably less flat than before, but it usually flattens again between massages. In my own experience I wasn’t convinced that massage helped much, because the natural position of the ribcage would always exert mild positive pressure to reinflate the lungs. I felt that the drugs and liquid paraffin (and possibly also the Taurine given to the mother) helped more than any massage I could apply.
You may observe that when a kitten is fighting for a teat or crying for its mother, the chest is much flatter than when it is at rest or feeding unchallenged, so using the lungs once they have gone flat stresses them. If the kitten continues to gain weight this is a good sign. If weight-gain stalls or the kitten begins to lose weight you may be losing the battle, BUT this may just be because of colic: burping the kitten by holding it upright and patting its back gently, and particularly dosing once a day with one or two drops of liquid paraffin will help this. If the underside of the ribcage collapses inwards so that pressure on the sides makes the centre of the chest cave in rather than push out, the kitten has less chance of survival.
What about using an oxygen tent to substitute the deficient oxygen for 3-day-old kittens? DON’T.
The atmosphere is composed of 78% nitrogen and 21% oxygen. Since oxygen is exchanged at the alveoli-capillary membrane, nitrogen is a major component for the alveoli’s state of inflation. If a large volume of nitrogen in the lungs is replaced with oxygen, the oxygen may subsequently be absorbed into the blood reducing the volume of the alveoli, resulting in a form of alveolar collapse known as absorption atelectasis – in other words, an oxygen tent would probably make lung collapse worse.
DOGS have problems with a condition similar to FCK, and breeders sometimes call it ‘Swimmer Puppy’. It seems to be very similar to kittens (although it may not be the same condition), and a useful website that suggests a way of helping the puppies may offer hope to cat breeders with FCKs.
According to this website, the normal sleeping position for a puppy is on its side, but ones that develop FC end up sleeping on the chest: this exacerbates the flatness, as well as keeping the puppy in an unnatural position, which may be bad for lung development. The key to the puppies is to force them to lie on their sides, and the breeders do this by a combination of sitting over the puppies and continually turning them onto their sides both when resting and when feeding, and also by putting them into a sock stuffed with cotton balls that makes a rounded shape on the underside of the body, thus rolling the puppy onto its side when it is relaxed. This does however squeeze the ribcage, and may retard the recovery of a kitten, which is much smaller and will find a tight sock much more restrictive than a puppy.
Kittens, however, spend at least 50% of their time lying on their chests under normal circumstances so, although lying on the side is not abnormal, it is also not abnormal for them to lie on their stomachs.
If you are not able to devote time to your kittens, then please give them to someone who can. It would be terrible to lose one of these brave little lives because your other commitments prevent you from caring for it. Think very carefully about continuing to breed if you cannot take time off to look after kittens if anything goes wrong: breeding is time-consuming and often requires sacrifices, and if your work or life prevents you from being there to support a struggling kitten then breeding may not be the right thing for you. I have been criticised for saying this, but I believe personally that it is true (and it’s my website!). We choose for our cats to breed, they don’t, so we have a responsibility to be there to care for them if they need it.
There are warnings to be aware of if attempting or considering splinting:
In late 2004 and early 2005 four breeders with affected kittens had success in taking action on the physical symptom (the flattened ribcage) by ‘splinting’ the ribcage in a corset and several breeders have since tried it successfully. Splinting would have the same effect as positive air-pressure treatment. The first two did this with a cardboard toilet roll, cut to shape. This was curled tightly around the body and tied in place so that it pressed on the sides of the ribcage, pushing the flattened underside back outward. The curved underside meant that even lying on its front, the kitten was not putting pressure directly on the ribcage, so its sleeping position was not making the condition worse.
One of the breeders who tried this said the tube did not make the kitten roll over onto its side (see below), but although lying on the side helps, simply lifting the chest off the floor of the bed will relieve the immediate pressure on the flattened area, allowing it to expand out naturally if it is able to do so. It is clear that pushing the sides of the ribcage in can provide immediate relief to a kitten that is having breathing problems. I think this could be a life-saving solution to the condition. We still don’t know what causes FCK (and there IS definitely a genetic component, or we would not be able to predict it happening in certain lines), but if this turns out to be an effective treatment we have won a very large battle. The puppy breeders use a sock, but because kittens are so much smaller and more delicate to handle, I think the toilet roll solution is far better.
Very few cases of FCKS are suitable for splinting. To find out if your kitten is suitable, lay it on its side when sleeping or suckling and put gentle pressure on the ridge of the side of the ribcage. You will be able to see if the breathing is easier or impaired when you do this Look particularly at the soft tissue below the ribcage: if the pressure causes the gut to be sucked inward more than when there is no pressure applied, you should not splint the kitten. Massage is the only alternative in this case, and even that may not help if it distresses the kitten.
Another type of FCKS which is not suitable for splinting is where the corset makes it more difficult for the kitten to breathe, or the distress makes the condition worsen. Some kittens are fine in a splint if they are resting, but cannot expand the ribcage sufficiently to draw breath when they are active. If your kitten falls into this category you cannot splint, but you should be able to massage without difficulty
If the ribcage is beginning to poke inwards, or the sternum (breastbone) is already poking in, pressing on the sides will force the sternum inward rather than outward and kill the kitten – make sure that before you try anything you are CERTAIN that the sternum will move outwards when the ribcage is compressed. Use your fingers to press the sides so that you can see what is happening before you put on a splint/corset, which will hide the thorax so you won’t be able to tell what is happening.
If you decide a splint is going to work, just put the roll on loosely and work on making the kitten lie on its side. This will make a difference even without putting pressure on the sides. It is always a good idea to consult your vet about anything like this, and he or she should be able to advise you on whether your kitten has an inverted sternum or not if you are unsure. Many vets are skeptical about information found on the internet: if this is the case, please direct them to this page where they can access the veterinary article for themselves, or else print the article off and take it to them.
Be patient and gentle – tighten the splint gradually in stages (over hours or days) or you could harm the kitten or break ribs by forcing. One breeder of Maine Coons had a kitten who was struggling with breathing, but as soon as she splinted him he could breathe again – this is obviously a type of condition that is different from the ones who are made worse by the splint. She is not the only breeder who has tried this and been successful. Splinting is easier with larger kittens, but the longer you wait before splinting or treating with massage, the more the ribcage becomes habituated to the abnormal shape, and the harder it is to restore it to the correct shape. Many thanks to this little fellow’s mummy, who kindly took these excellent photographs. He’s now doing very well and only wore the corset for a week.
Another breeder was kind enough to send me his thoughts and some photos of what he thought about this solution… ‘Your pic of a kitten in a cardboard tube would do nothing to keep kitten on its side or put pressure on his sides instead of front of chest. I did something else. The ridge keeps the kitten sleeping on his side and he can not put pressure on his tummy side’. Although some people seem to have been successful with the tube version, we have no way of knowing if the kitten would have survived anyway or not, so it’s a good idea to consider everything that may help. The younger a kitten is, the more likely physical therapy intervention will succeed, and the quicker it will show results. However you have to be careful if a kitten seems all right and you remove the corset, in case the chest flattens again. If caught within a few days of developing, a week in a splint seems to be enough to reverse the damage. Older kittens may need a lot longer. You can take the splint off to check the condition and massage the ribcage, though if it is hard to get it on and off in the right position then you may find it easier just to leave it in place.
Feedback from breeders is essential to learn more about FCK and different ideas and experience can refine our ideas and solutions. I am very grateful to Barbara, a Burmese breeder in Germany, who read this information and made a website with very clear and informative pictures showing her kitten and his progress with the splint. She and her vet also thought that the join in the tube should be below the ribcage rather than above the back, to encourage the kitten to lie on its side and her results were really encouraging. Sadly, Chester died after initially improving dramatically, but it is clear that the splinting did relieve his problems while he was alive.
More information from someone who read this page: ‘We have an FCK and we printed the information you gave on the internet and brought it to our vet so she could see about the brace. We made a brace/splint only we made it differently. Ours doesn’t go over the front legs. To make this brace use a soft curved piece of plastic about 1 1/2 inches wide and about 3-3 1/2 inches long depending on the size of your kitten. We got our plastic from an 8.75 oz Sunny-Delight bottle. Then took the plastic and covered it with horse wrap, so the plastic would not irritate the kitten. Envelop the 6” horse wrap around the plastic piece leaving enough of the horse wrap extended to go around twice. Wrap it snuggly yet comfortably around the kitten’s chest under the front legs. You should change the horse wrap every 2-3 days, for it loses its stickiness. (it sticks to itself not the kitty) Our baby is doing quite well.’
If splinting is done carefully it could save the life of your kitten(s), but bear in mind that sometimes the FCK seems to be caused by poor lung or heart development (or pneumonia), not the other way around, so even if the ribcage is rounded out again it may not solve the underlying problem, and the kitten may still die. However this is much more hopeful than any of the other things that have been suggested in the past, giving instant relief to a kitten having difficulty breathing. We do know that sometimes the internal damage is caused by the FCK and not the reverse, so please let me know if you are trying splinting, and please do let me know the outcome. The cases I have been told about so far are of single FCK kittens in a litter; it would be very useful to know of a case where this is tried with a whole litter that has gone flat, as the condition tends to be more serious where a whole litter is involved, and the mortality rate is higher.
There is a problem in applying a splint, or ‘corset’ to a kitten with FCKS, since the splint will be fine while the kitten is resting, but as soon as it needs to draw a deeper breath, the corset will restrict the movement of the ribcage, causing a sensation of suffocation, and the kitten will panic. This in turn makes it struggle and cry far more, and feel more restricted. Unless a kitten is happy with the corset during all periods of activity, it must not be left alone. This being the case, the owner may as well massage the kitten as put it into a corset while it is watched. Older kittens seem more amenable to wearing a corset 24 hours a day.
A more useful purpose of the corset is to prevent the kitten resting its weight on the flat underside of the thorax. In doing this, it encourages the flat position and effectively prevents the thorax from rounding out by itself. A tubular corset will allow a kitten to lie on its stomach (which is a natural position) without putting pressure on the flat chest. However if the corset is loose enough to ensure breathing is not inhibited, it will often slide off. There have been numerous ingenious ways tried of keeping a corset in place, however the construction must not prevent natural movement and inhibit the kitten from finding its mother for milk, or rolling upright if it gets tipped over. Since adequate nutrition is so crucial in survival, the kitten needs to be able to feed whenever it is hungry, and not just when the breeder is on hand to help it get to a teat. Encourage the kitten to lie on its side while feeding and sleeping. Kittens normally seem quite amenable to this. Lying on the side will help gravity to do what you would otherwise be doing by squeezing. I have also found that kittens who do not respond well to splinting can be helped by laying other kittens on top of them when they are sleeping, but ONLY if they are sleeping on their side! Be careful as, again, the pressure may not be tolerated by the kitten.
One breeder noticed a very useful side-effect of a corset: a kitten with both kyphosis and FCKS was put into a corset, which he tolerated well. After a little more than 2 weeks like this, the owner noticed that not only had the flattening improved and was almost normal, the spinal deformity had also improved and apparently disappeared. Without x-rays we don’t know much more about this, but it sounds as though the corset had a similar effect on the spine to an orthodontic brace on a child’s teeth, putting traction on the spinal compression by the shoulder blades and making it move into a correct position. This is worth consisdering if you have a kitten without FCKS, but with kyphosis.
Finally on splinting: some kittens are extremely distressed by splinting, and the distress it causes is counter-productive in attempting alleviate symptoms. One breeder reported that her kitten was gasping for breath after screaming because it did not like the splint. You need to gauge how the kitten is reacting to make sure that the pressure you are providing is not too great, and also that having a splint on is not going to upset the kitten so much that it expends too much energy fighting or crying, and that it stops feeding because it feels it cannot move. If you cannot splint because it distresses the kitten too much, then use massage and pressure on the ribcage to keep encouraging it to a normal shape. Do this as often as you can. DON’T do it while the kitten is suckling if it is distressed by it, but most seem to find it pleasurable (!).
Some vets also recommend making a flat-chested kitten move more by pulling it away from the mother so that it has to work to get to the milk, and also encouraging it to cry, though without distressing it unduly. The thinking behind this is that it will strengthen the muscles used in breathing and this may encourage the ribcage into the correct shape. Since we now know that the problem has little or nothing to do with the ribcage, but is caused by lung collapse or a badly developed diaphragm, and that stressing lung activity usually makes the condition worse, I do not advocate this approach: as described above, the effort of increasing lung capacity during activity causes the flattening to increase, and also I suspect the extra energy the kitten is forced to expend is not helpful if it is already losing weight because it is not feeding well.