Why is my outdoor cat rejecting one of her newborn kittens? Is it sick?

Poor thing. Sometimes mama cats can sense that a kitty has some sort of defect, so they will neglect them and focus on the healthier kitty. Also, if somehow the kitty was touched by a person and the mother no longer smells the kitty's scent, but instead a human, this too will cause the mother to neglect said kitty. Give it time and continue to monitor this kitty closely to see if she is getting fed and stimulated to pee and poop on her own. If she isn't, then it may be a good idea to separate the kitty and nurse her yourself until she can be weaned onto kitty dry food, which is around 3-4 weeks of age.

She may need to eat or use the litter box, causing her to leave them for a bit. She may have been planning on coming back. It could be that Oya is rejecting her kittens, which can happen. Some cats are poor mothers and will reject their kittens, while others will reject a kitten because they know it's sick and not going to make it. It can take time for a mother kitten attend to their kitten, and I would leave her and her kittens alone for 30 minutes in a room. Come back and see if she has groomed them, and/or started to feed them. If she has started bonding with them, then it's fine. If there is no evidence that she has started taking care of them, then you will have to feed them yourself. This requires a kitten formula and bottles. You can get kitten formula from a pet store or a grocery store. I will put a link below on how to care for newborn kittens. Best of luck, I hope this helps! https://www.2ndchance.info/orphankitten.htm

This is a very concerning finding, if the mother is actively taking the kitten away from the others she may feel this kitten is unwell and may be putting the other kittens at risk. I wold recommend a vet check for the kitten and mother to rule out any signs of infection and it may be worthwhile trying to bottle feed the kitten if rejected by the mother but success rate is quite poor if the kitten is unwell

Consider having it physically examined by your veterinarian. A mother's instinct is strong and the kitten may be sick or injured. If the exam is clear, it may be a case of abandonment and you will need to hand raise the kitten yourself. A kitten milk replacement, such as KMR, can be bottle fed for the next week or so and then you can begin weaning to solid food. This is done my mixing kitten food with KMR to make a gruel slurry. Gradually decrease the amount of liquid over the next several weeks until the kitten is eating canned food by 8-10 weeks of age.

She may be separating it because it is not "normal". It is important to weigh this kitten on a small kitchen scale daily to make sure it is getting enough milk. If it is not gaining weight, then you may need to take the kitten away and start bottle feeding it. The kitten should also be evaluated by a vet to determine what is wrong with the leg so you know what to do to help it best as it grows. If you need to raise the kitten, here is a great article to help: https://veterinarypartner.vin.com/default.aspx?pid=19239&id=4951456

There are a few possibilities: One, she is a new mother and is feeling a bit overwhelmed or doesn't know what to do with an entire litter, so she is just trying to move a single kitten with her. Two, there may be something wrong with the other kittens such as a deformity, etc, as some cats will try to push away or stop caring for these kittens if they sense something is wrong. Three, she will eventually move ALL the kittens, she is just trying to find a place that she feels safe and comfortable in before she does so. Making sure she has a nice cozy and private place to house her kittens may help her feel more comfortable. You may also need to start helping out and supplementing feeding for any kittens she is pushing away or is having trouble nursing. If any kitten or momma cat seems ill or aren't thriving, bringing them into your vet for an exam to rule out any illness or genetic issues is best.

Some kittens don't make it no matter what we do to help them out, and some cats are just not cut out to be moms. There is also the possibility that there is a congenital internal defect. If the kitten is very weak and won't suckle from the nipple or a bottle, you can try to slowly syringe the kitten milk replacer, but there is an increased risk of it going into his lungs and causing aspiration pneumonia. If this doesn't work, you should take the kitten to get checked out by a vet. The vet can show you how to safely tube feed the kitten to get its proper nutrition. Make sure that the kitten is staying warm and clean, and that you are stimulating urination and bowel movements. Here is a good article on raising orphan kittens: http://www.veterinarypartner.com/Content.plx?P=A&S=0&C=0&A=576