Why is one kitten in my litter so much smaller and weaker than its siblings?

Hi there again, cats can breed multiple times to multiple males during their heat. So it is possible that the smaller Kitten has a different DNA makeup and it is also possible that it may be a day or 2 younger than the others if if was from a later breeding. Of course there is always a possibility that something may be more concerning with the kitten such as an internal birth defect. Keep weighing them to make sure they are all gaining weight daily. If you have any concerns please have them examined by your veterinarian. Best of luck and thank you for using Pet Coach.

Poor Shadow! This could just be her normal. Cats can actually have multiple dads from the same litter so it is possible that her dad was a more petite cat. There is also the possibility that she has a genetic issue that prevents her from growing normally like poor absorption of nutrients or a liver shunt. If she is completely normal, then I wouldn’t be overly concerned. If you are concerned or if she doesn’t act like the others, then I would talk to your vet. Your vet can do some blood work, fecal and possibly even X-rays, an ultrasound and specific GI bloodwork if needed to see what could be causing the poor growth. I hope this helps!

Hi and thanks for posting on Petco Pet Education Center, formerly Petcoach! Lack of growth and failure to gain weight in a kitten can be due to a number of medical causes- viral or bacterial infections and parasitic infections could be potential causes among others. I would recommend having the kitten seen by a veterinarian for an exam and assessment. You may wish to bring a fresh fecal sample to the vet appointment in case your vet wants to test the kitten's stool. I hope this helps and thanks for using Petco Pet Education Center, formerly Petcoach!

A newborn kitten usually weighs about 100g. So the small one is a normal weight and the big one is really big. They will gain about 100g/week. So if your smaller kitten gains about that much/week, it is getting enough milk. Mama has more nipples, so it will likely be able to drink while the other is suckling somewhere else. Just observe them. For now I would not worry.

The best thing you can do is to weigh her twice daily to make sure she's growing appropriately. Kittens should gain 10% of their birth weight per week, or if you don't know the birth weight you should make sure the kitten is gaining weight each day and not losing weight. If she is not gaining weight it would be a good idea to see a vet for an exam and potentially to supplement with bottle feeding.

I agree that it sounds like Buckwheat is the runt of the litter, and they do tend to struggle more than their littermates. You are doing the right thing by supplementing with KMR, and he's unfortunately still too young to wean him. I'm not sure how often you are feeding him with KMR, but I would discuss with your vet increasing supplementation to try to get him to gain some weight. Also make sure he is up to date on his deworming treatments, as intestinal worms can prevent him from gaining weight. Finally, I would have him seen by your vet to discuss additional meals with KMR and the vet may have other suggestions to help him thrive.

Sometimes kittens are born as dwarf and will not grow much. This is a rare congenital disorder. More often kittens that do not thrive or grow normally have a congenital heart defect or a liver shunt. I suggest you have Foxy examined by a vet to rule out the latter problems, as there will be healt implications for her future life. Here is some information on those conditions: https://www2.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/portosystemic-shunt https://www2.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/congenital-heart-disorders