Are dust baths absolutely necessary in the winter? I ask because I've just had to block my chickens from getting into the dust baths because the dust coming off of them after a bath is horrendous! There is dust on EVERYTHING in the run and they are wheezing. It's definitely the wood ash I added to the mix that's making all the dust. The run is wood chips and the coop is wood shavings. But they don't spend any time in the coop unless they are sleeping. So, if dust baths are necessary, I can put in a temporary dust bath, but what should I put in it? Just sand?