Prevention and management of upper respiratory illnesses in backyard flocks
Denagard: https://amzn.to/3Zzb237 Mix one TSP of Denagard per gallon of water. Add a tbs or two of raw unfiltered honey. Mix well and serve to your chickens for 5-10 days. Add two TSP if you are losing chickens to respiratory illness.
One natural water additive we use for prevention and management of upper respiratory ailments is oil of oregano with peperine we get from from Peter Brown, aka chicken doctor (First State Vet Supply).
We also recommend and use is Nubiotic from Amazon. Directions are on the bottle
Adopt good quality bedding. We use and recommend hemp. Hemp is natural and has virtually zero dust, and it is a wonderful absorbent. Your coops will not smell. Apply a couple of layers which will last 2-3 months. Hemp is also great for the soil. We only purchase hemp that is grown and packaged in the U.S. and Canada, with exception of the high grade Aubiose, which comes from Europe (Aubiose is grown in France). We purchased a tote from J Bean Products. It lasts a long time.
One item to keep in stock in your avian pharmacy is VetRX Just a couple drops on the comb, waddles, under the wings kisses the cold away.