our rats must have teeth like beavers... they will eat their way into or out of any shed, coop, pen, either they or mice chewed through the lawnmower cable, a dog harness, and a watering can that were in the shed!
we have water butts on pallets at the side of the goat shed - the rats just run under it to dig the tunnels, and have come up through the floor (its not on a concrete base)
I want hen feeders that wont get filled with muck as well as being rat proof - the disease aspect concerns me most