I have a male duck and two female ducks that live in a coop with my 13 chickens. My male duck's part was pecked at by chickens and is swollen and red. He's eating and drinking normally, and just swam this morning. I plan on separating him and giving him a nice, warm bath and washing him with some Dawn dish soap. It looks like his area is infected, so would it be alright to give him some penicillin or amoxicillin? If so, how many mg a day and for how long? If not, what can I give him?