Do you have your chickens on a worming regiment? Do you worm regularly (every 6 to 8 months)? Have you wormed recently?
Pretty much every "illness", sneeze, horseness, droopiness, etc. with my chickens were all solved when I wormed correctly... twice with Valbazen is what I had and used, I was able to buy a few CCs from the guy at the feed store who had an open larger bottle. Then (a little) Seven Dust in the on the chickens ten days after that.. on the ground, cleaned roosts, and cleaned nesting boxes anytime, weekly?
Cats sneeze when they have worms... I don't know if the same is true for chickens, but mine stopped sneezing after worming. Just a thought.
1/4cc Valbazen for Bantams... 1/2cc Valbazen for Standards.. given orally. Do not eat eggs or chickens.. withhold for a total of 24 days... give once, wait ten days, dose a second time, wait 14 more days... safe to eat eggs on 25th day.
You can use Eprinex on the skin and then Valbazen (orally) ten days later... dosage and withdrawal period would be the same. Eprinex kills mites as well (Valbazen does not kill mites)... But, Eprinex does not kill Tapeworms (Valbazen does).
Look for recent posts by dawg53 for the best info on worming. Search Valbazen and/or worming... check dates on posts.