[AmityvilleHams]

Hamsters don't hibernate though,they go into torpor which is very different.Hay is not a good idea for hamsters,as it is a very rough material and can end up causing injury plus it could mold whereas it would be far less likely to happen if you just used plain toilet roll.

Instead of a heating pad which is risky and only a temporary fix,heat the room.This is much safer,more controllable,more reliable,and you won't have to worry about having inappropriate temperatures like with the heating pad(which still won't eliminate the entire problem,as it only heats a portion of the cage compared to making an entire room a suitable temperature with some alternative).