I have 4 aprox 4month old leopard tortoises. I was told by my breeder, very experienced and reputable to put hay on top of the peat and sand mixture so if they flip they can flip back easily. It seems to work. I spray water under the hay on one end where the heat is . I remember someone talking about mold. There is no mold when sprayed underneath. Are there any other concerns with using the timothy hay that I'm not aware of ?