Sometimes kitties who've had many litters, will birth unformed kittens. I had a gorgeous white english or british shorthair white cat I rescued years back. Mama delivered I forget how many kittens now, but all were stillborn. One I thought was afterbirth and found out it was a kitten, but without developed skeletal structure, and another was hairless. What a sad thing to witness, but the cat got up after it all and acted like she'd had so many litters and lost them, she could care less about another litter. She was tested etc. and got a wonderful home. It's sad to go through, but maybe meant to be.