Help hen having trouble breathing, pale comb!

[1 true Phoenix]

Dear, I think its Chronic respiratory Disease (C.R.D) as the symptoms you mentioned relates to it. I can suggest you homeoathic medicine if its available near you. Sneezing, Coughing Antim Combination of Thuja200+Nat sulf200+Carboveg200+Bryonia200, 5ml each in 8 liter of water for 100 birds for 3 days.
Regards
Tomson

Would the chicken have the yellow spotting in mouth/throat if it was CRD?

 

[Eggcessive]

Many diseases can cause yellow plaques or “caseous material” inside the beak, throat, esophagus, and trachea. Without a culture, it is hard to know if it was caused by a virus, a bacterial infection, a protozoan infection, or a fungus. That is why it is always good to either seek testing if available, or get a necropsy by the state poultry lab to get a diagnosis. Necropsies may be inexpensive depending on the state, and sometimes they will do more than one bird for the same problem.