Wobbly Three Week Old Kitten

My sweet girl, Sophie, had her first litter of kittens three weeks ago. There were only 2, and there was a noticeable size difference so we've been calling them Big'un and Littl'un. When they were a week old, I was really concerned about Littl'un bc he had very odd muscle control and constantly twisted his head and body to the left. After another week, he'd begun to roll around to get back to mom and neither if he got separated. We were very concerned, then this week, he has started walking, and holding his head much, much better. We're just ecstatic, needless to say!!

My question is, has anyone else experienced this with a kitten? Did he continue to get better? I'm also concerned about his eyes, are there any indicators we could look for at this age for blindness? I can't tell if his eyes are quite right and if maybe that has sobering to do with his balance?

This is the babies at one week

See how Littl'un on the left has his head turned?

I'm glad to hear he is doing better.  There are several things that can happen in the uterus that can cause kittens problems with mobility as they grow.  Watch him carefully and mention this to the vet when you take the kittens for their first worming and shots, or take him sooner if it doesn't appear to be getting better.  It could be something as simple as the way he was positioned in the uterus, or something as complex as problems with his brain development.  Three weeks is a good age for them to achieve because usually if their problem was going to be fatal, they would no longer be here.  Hopefully he can outgrow his handicap, and if not, he will be just as loveable but may require more support and protection as a special needs kitten.  They are very adorable kittens!  Thanks for including the photo.