It's likely Avian pox.
Does it look like any of these:
https://www.backyardchickens.com/LC-diseases-AvianPox.html
Avian pox is a virus so there's no need to treat with antibiotics. The lesions (sores) can sometimes become infected with bacteria as a secondary infection. To help reduce the chances of that, dot each sore with a q-tip soaked in straight iodine. On sores near the eye, use Neosporin ointment. On sores near the mouth, use a q-tip soaked in Listerine. Then Iodine.
Support his healing and the others' immunity (as they could be fighting this asymptomatically - without symptoms) with vitamins. Cod liver oil or fortified (read the label for A, D, E fortification) sprayed on the feed twice weekly during the illness. Use a travel-sized hand-held spray bottle from the cosmetic section of drug stores or
Walmart for that. Fortified wheat germ oil can be found in many feed stores in the horse section. Cod liver oil should be pourable, not in capsules. The vitamin A helps mucus membrane health. The vitamin E increases skin healing and provides anti-oxidants as well as being naturally anti-inflammatory.
If any birds get a secondary infection (localized swelling of the skin, particularly near eye or mouth lesions) then use Penicillin injections for a period of a week to cure. Penicillin G procaine is readily found in most feedstores (their fridge). Buy 3 cc syringes with 18 gauge needles. Many feed stores sell the 3 cc syringes complete with screw-on 25 gauge needles but those needles are too small. Just buy the loose 18 gauge needles remove the 25cc ones and replace with the 18 gauge just before using. You must shake penicillin for what seems like hours before using as it's stored in the fridge and the particles of the medicine settle on the bottom. When it's done, then pull the amount of med you need and while it's in the syringe let it come to room temp. (Put the big vial back in the fridge). PM me with whatever penicillin you get for a dosage if you have to do this.
You shouldn't have to worry about secondary infection if you treat all the lesions. BEST way of doing it would be remove the lesions but they're very very very hard to pull off. You can try dotting some not near the eyes/mouth with hydrogen peroxide to soften them. But at least dotting with the strong straight iodine should help.
If you see any lethargic birds, symptoms or not, pull them to the side and isolate. Check them carefully for cheesy exudates in the roof of the mouth.
Normal:
Wet pox:
In any case, if there are any changes please update *this* thread as you'll have at least one subscriber (me).
By the way, this takes about 4 weeks to clear. There might be more lesions, others might get them (no need to isolate - it's most often spread by insect vector anyway so likely they've all been exposed or will be), some might not show any signs. All birds who are exposed and get the virus (symptoms or not) will thereafter be completely immune. YAY!
In my case the scabs stayed on the full 4 weeks and then dropped off in one day. In my chickens, I noticed that the scabs looked more brown than black two days before dropping. The edges seemed to pull away from the skin and look less dark. Then they were all gone in a day. If you can, remove the bedding and discard (throw away - don't dump elsewhere on the property) as the scabs are infective.
If you have turkeys be prepared as they get it and they get it VERY badly. If you ever get turkeys, and keep them on the same grounds then I'd highly consider vaccinating for pox. You can also vaccinate your new birds for it, but usually pox is more cosmetic and a little decreased immune system and not a big issue. The main thing is to watch for lesions near the mouth and eyes and treat them very thoroughly.
Please let me know if I can be of any help to you at all.
