A few months ago my chickens developed blisters on their combs. The blisters are white and filled with clear liquid at first then after a day or so, they turn yellow and the skin area around the eye and wattle turns white. They also seem to want to scratch the area. Been to the local vet, they didn't know what it was, but they gave me antibiotics and some topical antibiotic cream which seemed to clear it up but it keeps coming back. They seem lethargic and egg production drops off. I don't think it's pox as the blisters are not dark. Can anyone help?