i recently moved my four chickens out into their coop about a week ago. They are exactly 2 months old now. I last checked on them at 2 pm today and I just got back at 6:30. All the chickens had blood around their comb. There was no blood on the ground or anywhere else. Just on their combs. Some worse than others. They are eating and drinking fine. What could have caused this? Should I be worried? How should I treat it?