I have Barred Rock hen who was injured badly by one of our roosters or other hens. We brought her in the house all day yesterday and last night. We had cleaned her wounds the best we could and have her safe and warm in a basket in the kitchen. Her left eye is badly injured - due to black crusting scab and swelling we cannot determine if the eye itself has been pecked out. She also has wounds to the soft tissue to the left of her beak. She was eating and drinking and even laid an egg in the basket yesterday. Today we decided to let her have the freedom to roam in the coop (isolated from the flock) during the day. When we brought her back in the house this afternoon we noticed pronounced swelling of her throat area. I feared an abscess was forming possibly from drainage from her wounds. I attempted a needle aspiration of the swollen area but was unable to remove any fluid. I suspect a cellulitis type of infection. She seems more lethargic and less inclined to eat and drink this evening, perhaps because it is the time they normally roost. I want to administer an injectable antibiotic but am not sure if that is the correct treatment. I have seen Tylan 50 mentioned several times on this site and wonder if that would be an acceptable antibiotic to use. She is a sweet girl and we hate to see her like this. Any advice would be appreciated.