I have 4 kittens '4 weeks old mom feeds them three times a day they won't eat solid food yet I have tried offering kitten caned and they won't eat it they just want to nurse off mom.any advice.

Mom will kick them away when she wants to wean them. Keep offering a small dish of kitten (canned) food or soaked-in-water dry food. By five weeks, they will probably start to nibble on it.