I have learned over the years that sudden weather changes causes bacteria in the soil to go from dormant to active and this is what can get chickens to become ill.
Chickens can get sick from standing in wet puddles. sometimes rain just happens. But be prepared and know that a dry area is where you need to move the chickens as soon as possible.
When weather changes and the ground changes from "wet to dry" or the temperature changes form 90 degrees and drops to 30 degrees (it happens in Texas a lot of the time) this sudden shift in temperatures changes the way bacteria act in the soil. Bacteria goes from "dormant to active" and this in part is what causes sudden chicken illnesses.
