Here's what I know about the difference between a bleach/water solution (from 5% to 50%) and a vinegar/water solution (also 5% to 50%). Bleach does not clean anything, though it does disinfect, however, once bleach dries it is inert. This means that bleach does not reactivate or continue to disinfect should it become damp again. Vinegar, on the other hand, is an excellent cleaner as well as a disinfectant. It also will reactivate once it has dried and been re-wet. For these reasons vinegar is a more efficient solution when cleaning and killing mold and mildew. 
Vinegar does emit a lingering unappealing odor -- I combat this by adding drops of essential oil into the spray bottle HOWEVER, do not use an oil that can be harmful to the chickens such as rosemary oil or any of the mints. 
Bleach can be dangerous for the chicks/chickens should it come in contact with the ammonia aspect of chicken feces. 
Having said all that, my preference is a 30% solution of vinegar to water, which is surely stronger than necessary. 
Jenny