Sheds with runs

My bunnies always go outside in the rain, and get wet paws and then go back in the shed and get it all wet!
I tried a doormat but they just wee'd on it!
it makes the shed floor a right state. whats the best thing to do? is there even anything?

How about a litter tray in front of the doorway full or hay or whatever, so they have to hop through it on the way in.
Or you could try a towel, but as you say they will probably just wee on it :roll:

Oooh i could put a litter tray there yeah. at least if they wee on the litter it can just go in the bin.