I recently required three young Western Toads, and need advice on how to care for them. They are currently in a Sterilite 32 quart bin, is this enough room? I have been feeding them about 20 mealworms every other day. I am using plain dirt from my backyard for a substrate (Clean of chemicals), and am wondering if beach sand substrate or a beach sand and dirt mixture would be better? I am also hoping to keep one of them through winter, can they survive in below freezing temperatures? Once again, the is my first frog or toad, so any help would be appreciated. Thank you!