I have geese and ducks together, they have a pasture that is large and green with grass, but I also have a small wooden fenced in area with their shelter inside that fence. I just lock them into the wooden fence at night and they choose if they go into the shelter or not...mostly not, unless it is raining for days on end and they need a break. I have very fine wood shavings and then a thick layer of straw on top of that inside the shelter which works great. outside there is some grass around the edges and lots of leaves that fall and build up around the sides due to the wind, which is the problem. The center area is just bare dirt or mud if its raining, everything I put down is blown to the edges of the fence. I have some heavy "wood chips" they are more like tiny wood cubes or chunks. They'd stay put but I'm afraid the birds will eat them or hurt their feet walking on them. I've tried straw, wood shavings, leaves, even sand blows away once its dry eventually. The only other things I can think of are the wood chips or something like pea gravel, I feel like both have their problems. They are only in this area from about 10 pm to 9am most of the time they are sleeping. Its just a muddy ugly mess right in the center and its making me nuts.