What did the vet give you to spray in the coop? Do you remember the name?I has some kind of a virus disease in the flock some weeks ago, and vet gave us a powder to dillute in water and spray the coop with. Some chickens even died from the disease but it didn't show any symptoms similiar to this crowing. What should i search for in the beak?
When you look inside the beak see if there's any white or yellow spots in the roof of the beak, sides and in the throat.