Infectious BronchitisI've posted about this before but my question was only answered with questions. I have a flock of 16 chickens, and 6 guineas who live separate. Within the past 5-6 days one of the Gold Laced Wyandottes started breathing weird and eventually got worse so I brought her inside. I would like this to be cleared up soon because we are possibly getting more birds soon. I have done research and have not come to a conclusion as to what it is. Here is a video, this is when she was in the coop a few days ago, the breathing has gotten worse, at the end is were you can here it best. There is not external signs of parasites, no redness in her throat (although I have not checked in a couple days, she is by far the most difficult chicken to check down her mouth). Some times when she breaths she extends her neck and looks like she is yawning, her breathing has stabilized and is not getting better or worse. Another strange thing is whenever she breathes while I am holding her you can hear a fleshy pop or click, sounds like when some people push their toe against something and repetitively click it almost as if it is slipping in and out of the joint. This sound is coming from her left hip area and I can actually feel vibration whenever it happens. I think it may be air sack mites but there is not a whole lot of information for diagnosing it on chickens. Here is a list of my suspicions rated from highest to lowest possibility (my opinion) 1. Air sack mites. Seems the most likely but have had a hard time finding information on how to diagnose. 2. Infectious Bronchitis. Many symptoms match but there are still a few missing pieces. 3. Marek's. My flocks have been exhibiting some behaviors that resemble Marek's, yellow poop (only for a short period of time from our rooster), head bobbing and swinging (one pullet has been doing it for the past 3-4 weeks). I doubt this is the case but Marek's is quite common and can cause tumors which in turn create breathing issues. Extra information: She has laid an egg since being in the house, but the chickens in the coop have slowed down egg laying, they went from laying 12-15 eggs a day to now 9-10 eggs a day, directly after I removed the chicken from the coop. Final question, I am likely to be getting more birds soon, more egg layers, possible turkeys, meat birds, quail, ducks, etc. Should I be worried about Marek's (or any other highly contagious lifetime illness). and it possibly spreading to more birds?