Hen Wheezing

[Sunflower Dew]

Our 1 1/4 year old RIR hen was breathing harshly this morning and over a few hours has progressed to a sort of trumpet-like noise. It sounds like a failed note. She's opening her beak to breath, and is sneezing. It seems to be made every exhale. She was fine last night. The chickens have free roam of the backyard.
She is lethargic and stands still, making the quiet trumpet noise. Her comb is red, maybe a little more than usual. Her eyes are clear and there doesn't seem to be anything else wrong with her except the sneezing and loud breathing. Her crop isn't squishy or swollen. She's holding her wings at attention. Her vent is clear. The noisy exhale gets worse when she is stressed.
She's a pet, and we would really like to know what's wrong. Any suggestions or other info I need to give?

 

[Eggcessive]

Open her beak and look inside her at her throat and airway for anything usual (like some stuck object) or yellow cheesy patches that could be fungus or virus. Has she had fowl pox lately? This may be a respiratory infection also, so you might want to get her on an antibiotic such as Tylan 50 injection, Terramycin, or gallimycin from the feed store. Dose of Tylan 50 is 1 cc or ml daily as a shot into the breast for 3-5 days for a chicken over 5 lb, 1/2 cc for under 5 lb, and 1/4 cc for bantams. Tylan 200 is sometimes the only one available, and the dose of it would be 1/4 of Tylan 50. Use a 20 or 22 gauge needle and only go in a 1/4 inch. Here is link for common respiratory diseases such as mycoplasma, infectious bronchitis, and coryza: http://edis.ifas.ufl.edu/ps044