I have searched everywhere but haven't found any answers to this.. My 2.5 year old hen is breathing quite heavily, but with her mouth closed. When she is laying down, her whole body rocks when she breathes. I can really notice a sort of contraction in the throat area. She is acting fine otherwise, eating, drinking, pooping, laying... I'm just worried as this is not normal breathing. I can barely notice the others breathing, so her heavy breathing is very obvious. Please help!! what could this be??