Concerned about Renzo

My little kitten Renzo continues to worry me. He is 7 weeks and half the size of his siblings. He only has 4 teeth beginning to come in. He still has a flatter face and little ears. I have watched him eat and often feed him extra. I tuck him in my double tank tops to carry him around with me so that I can give him extra milk,food and he is very attached to me. He waits by the door to come out with me and loves to sleep with me. He is the cutest little guy.
He uses the litterbox fine. The others groom him but are sweet to him too. They generally don't wrestle with him. Lucia nurses him still and mothers him. But he is teeny tiny still. He still has the roundness of a kitten half his age. He doesn't walk like the others he kind of does this hunched crawl walk.

Not the best photo but this was taken last week.

Has anyone had this experience? Should I be concerned?

Is he still the same or has he improved?

Was he the runt of the litter?

There could be alot of reasons why he is that way. My Oreo looks like a 6 month old kitten and she just turned 1 last friday. She was the runt and has fcks. I would have your kitten checked and see if there is a reason he is like that.

Originally Posted by mews2much

There could be alot of reasons why he is that way. My Oreo looks like a 6 month old kitten and she just turned 1 last friday. She was the runt and has fcks. I would have your kitten checked and see if there is a reason he is like that.

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I remember you mentioning the fcks. So I have an appointment for him with my vet.
He is indeed the runt of the litter.

Update:
He has grown some but he still has a baby face. I have grown so attached to him that I don't think I can let him go. His vision is still not good and he seems like he can't see that well. So every night he sleeps on my neck as I monitor him.