Today my cat gave birth. One of the kittens has both of her back legs deformed. I don't think that she will be able to walk. And I don't want to put her to sleep. I was wondering when she gets bigger if there is some kind of surgery that she can have to help her walk. Or maybe some device that I can buy to help her walk.

You should take your kitten to the vet right away.

Right now, I would suggest letting the mama cat take care of her kittens. Removing the kitten so soon will assure Mama will reject it, which we do not want her to do.

Boncatgirl, I know it is hearbreaking to see this little one like this. But, don't jump into anything just yet. The mama cat's natural instincts will take over and she will do what is best for her kitten. I know this is not something that you want to hear, but in the animal world, survival of the fittest always applies. Considering this baby has this birth defect, there might be something else wrong with it, and instinct will guide the mama cat as to how best to deal with her baby. If everything else seems to be okay, please just step back and let mama do her thing. If the baby is meant to survive, she will. Later on as she gets older, you can take her to the vet to see if surgery is an option or if there is anything else that can be done. Right now, all we can do is to make a guess as to your question because we cannot see the kitten.