I had a question about dust baths, about how old will they be when they start using them and do they need to be taught by an older hen or is this something they just tend to figure out on their own? For a small amount of hens (3) would a small plastic under bed container filled with sand or just plain ole dirt be ok or do you think they'd need more. I believe the dimensions would be about 3 feet by 2 feet and 2-3 inches deep. As for the heat would the use of a light garden mister in the run area be helpful to cool them off or do you think that would just be a waste?