I know, the joint seems quite swollen compared to the other. I cannot straighten the leg when very gently trying to, but he can retract it fully which gives me hope that the leg is not completely damaged. I suppose it is possible that he wrenched his knee during his hatch last night and like I said he was very late. Unfortunately, he cannot stand up which makes life difficult for feeding. I have given him a few drops of diluted nutri drench and he is sleeping quite happily now but we shall see. I took him to see my other chicks for some company but of course I cannot leave him amongst them. Thanks for responding.