My 7 mo old cockerel is squeaking. He does this quite often and has been doing it for a while. I have now noticed other birds in the flock doing the same. I have owned chickens for 6 years and have never had them making this sound on a regular basis. I have treated the flock with anti-biotics but many are still making this squeak sound. I have a couple of others who sound kinda flemmy and are puffed and obviously feeling under the weather, however the squeaky ones are having normal behaviors. I have no idea what the even begin to do or what it could be. Ideas? Suggestions? Thanks.