My barred rock is @ 8 months old. He lives with 9 others his age. All of the sudden last week he was flopping around. Hard for him to balance. He eats and drinks ok and can walk short distances but then sits on his legs. Sometimes he loses his balance and flops over. The others are not having issues. We separated him from the other but he flew over the fence back into their pen. Any ideas as to what his problem is or what to do with him?