Cat Chat Feline Forum

So we have a family of outdoor cats. A new litter of kittens was born about 4 months ago. There were three kittens. Two of them are perfectly normal kittens but the third, which we have named Gilbert, isn't normal. She doesn't move. She seems perfectly healthy and functional but she doesn't do anything. She will sit on the walking path and not move when you're walking through. She's not phased by anything. I can pick her up and she's limp. I can't tell if she's afraid or not because there is no reaction. She doesn't move out of her current spot to urinate or defecate but she seems to be keeping herself clean even though I never see her cleaning herself. I know she can move because she's has two spots she stays. Either the middle of the walking path or her box with blankets and a heating pad. What the hell is wrong with this cat?!! Is mental retardation a thing in cats? Is this just her personality and temperament?

I assume you've taken her to the vet - what have they said so far?
It could be that she has something wrong with her eyesight or hearing, or both? But you'd still expect her to explore. Does she respond to loud bangs?
Those are clearly the spots she feels safe in - is there anything there that differs from other places?
She must be doing something else as she keeps herself clean. Also, maybe she does things at night, and that is her safe spot for the daytime.
Did her mother reject her / is she the runt of the litter?

I have to agree that if she hasn't seen a vet she needs to be. It could be there is something wrong with her eyesight, her hearing or both, or it could be that something happened during birth or fetal development and her brain either didn't develop correctly or was damaged. You say she doesn't move to urinate or defecate, does she just do her business and then lie in it or move away afterwards. This to me is perhaps the most concerning thing, even blind kittens normally use a litter tray well enough.

I would also have concerns about her being an outdoor cat regardless of what is actually wrong with her, it sounds like she is very vulnerable to any type of predator or even just a general accident.