My vet (and they are farm vets) doesn't do chickens. sigh. But, I suspected one of my best roos had infectious synovitis, asked him if he could give me anything for it, and he mixed me up a powerful antibiotic I had to inject daily into the rooster's breast muscle. Even if vets won't do chickens they can tell you dosage and what is safe and effective. Sorry, you might want to check out the pet forum. There are some pros who frequent it, and they might be able to help.

Sounds like Bumblefoot. She should check the underside of his foot pad and between his toes for an open wound, usually older by now (no blood, just a hole) and packed with dirt. The warmth, limping and swelling is caused by the infection, and it won't go away or improve by leaving the wound uncleaned and treated--it's a tough micro-bacteria.

She'll need to soak his foot in warm water and clean the dirt out of the wound (hard to do, use a toothbrush and lots of patience), dry it, pack the wound with Neosporin and wrap the foot SECURELY to keep dirt out and the Neosporin in. The warm water soak is really good to help heal his foot too, the wamrth stimulates blood flow in the foot which carries the toxins away. She may also have to keep him off of dirt (and NOT in a wire bottom cage unless that foot is padded really well) unless she's wrapped the foot super good and he can't get the dressing off. He'll hate it, so he's going to try, his flockmates are going to try...so make it secure. Eventually he should accept it and leave it be.

Bumblefoot can take a long time to heal, and she'll need to periodically removed the dressing, clean the wound and repack it with more Neosporin. But dirt MUST be kept out of it during the healing process or she'll find herself, and her roo, right back at square one. You can't take shortcuts with Bumblefoot. :(

Velvet ~:>