Roo with broken foot?
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Feel of his leg joints to compare them for any swelling. Feathered legs can be a pain to examine for anything. Check the bottoms of his foot pads for bumblefoot (dark spot, redness, and swelling.) I would pen him up for 1-2 weeks with food water, and poultry vitamins to see if he gets better with rest. A dog crate would enable him to stay with the other chickens.