OXINE!
I am not a big fan of chemicals, but my research on Oxine (chlorine dioxide) has resulted in this product being used as part of my own backyard poultry biosecurity/health regime. I feel it is safer than bleach, it breaks down quicker, and even the World Health Organization realizes its super-efficient ability to kill bacteria, viruses, and PROTOZOA. (Does it work on coccidia? Hmmmm . . .) It has been used in the cleanup of natural and man-made disaster areas, and it has actually been around since the 1940s.
I bought mine from First State Vet Supply, and I use it in three ways: 1) cleaning-strength solution for my waterers, feeders, perches, and periodically in the coop itself; 2) misting/fogging strength in the coop occasionally (at night) to prevent respiratory illness and to eliminate coop bacteria, mold, and other pathogens ~ and I do it EVERY night if I start hearing any sniffling or sneezing; 3) safe dilution in waterers one day a week to reduce harmful bacteria/protozoa in the digestive system (it is important to also rotate a probiotic afterward to restore helpful bacteria to the gut).
My own approach is to reduce pathogens to a reasonable level and strive to keep my birds fit, clean, well-fed, and low in stress. I figure if they are in good shape and I practice good sanitation, their natural immunity will protect them better than medication. I like prevention much better than treatment.
Hope that info helps!