This morning when we let our Rhode Island Red Roo he looked like he was doing the backwards chorus line routine. He was kicking backward and hopping around. We caught him and in the crook of his leg where his knee bends he has a swelling/lump-nothing really excreting as if it's an abcess-it's just swollen. The other knee in the same place where it bends has a crack in it. What is this?? Could it be from heat? Do chickens get fungal infections? We put some peroxide on the knees, but aren't sure if we should dose him with some antibiotic? Sulfa powder?? I have never had anything like this and none of my other birds have it. He is an older roo and is quite heavy. Any ideas?