Hi. I am trying to put together a good cage with a lot of jumping and climbing room for my new rat and don't know what types of materials are safe for them. I can find a lot of "cage" like material, but a lot of the wires are painted or plastic coated. Is this bad for the rats, will they get poisoned or sick if they chew on them? Is galvanized metal bad for them? Any advice would be very much appreciated. Thanks!