My waterfowl overnight in a stall with pine shavings that the chickens walk around on during the day (waterfowl go out into a big pen every day). Since ducks and geese are prolific poopers (and the chickens roosting on the rafters above at night contribute their own poops too), I remove the top 2" of shavings daily and put on a fresh layer.
The removed poop-filled shavings, believe it or not, go immediately to top-dress my garden beds: shrubs/trees, perennials, veggies, flower- and fruiting vines, and bamboo "groves." Because there is such a thick layer of mulch everywhere, the fresh poop doesn't burn or harm the plants. The poop "dissolves" down through the shavings and doesn't sit on top, so there are no flies and no smell.
Pine shavings use a lot of nitrogen to break down (actually, it's the microscopic critters in the soil that use it as they eat the cellulose of the wood, etc.) so the poop replenishes any nitrogen taken from the soil, and soil microbes quickly digest the poop too. In less than 3 months, each layer of poopy pine shavings becomes rich garden soil.
If you don't like the idea of spreading fresh barn-cleanings, then it's better to have compost bins, barrels or piles that you can manage, turn, and dispense as they mature into "finished" compost.