I have (8) 9 month old chickens(first time owner) that have been doing great with the exception of some feather picking by a couple One in particular has a lot of feathers missing on rear around the base of her tail. I've noticed in the past couple of days how red it has gotten - no blood or injuries, but it is a speckled rash, almost like hives. I thought it might be from our cold temps and high winds the past day or so and she just had chapped butt! I tried coating with vaseline but it doesn't look any better today. Any thoughts?