My son is about 17 months old and still will not feed himself, he has never put a cracker in his mouth without me putting it in his hand and basically making him do it. Sometimes he lets you do this, sometimes he resists so I don't force him. He has never been one to put things in his mouth, only chews his fingers when his teeth are bothering him very occasionally he will suck the side of a box or toy but he never puts anything small in his mouth.
Has anyone else encountered this or any advice would be most appreciated.