Is vaseline needed? It frosts around this part of norcal a few times every fall/winter. Tonight the weather is supposed to get down to 30F with a frost warning. My girls are inside the coop at night and there is pretty good draft reduction. If it's 30F in the coop with adequate moisture ventilation, do I need to put vaseline on their combs? If I need to I will, but if most don't think it'll be an issue then I don't want to make more work for myself. Thanks!