My year and half old Araucana rooster has recently started having a quiet, muffled voice and loud breathing like his throat is obstructed or there is mucus in it (like a person that has lost their voice). Everything else about him is normal; he is still eating, drinking, mating, and acting like a normal chicken. Any ideas? If he's sick I want to isolate him from the rest of the flock but everything besides his voice and breathing is normal.