i use horse stall pellets (wood burning stove pellets with no accelerate works just the same)... You have to wet them down with a spray bottle (and i use a green non toxic odor killer too, it abosrbs into the wood and does it's job when them poop). My ducks live inside, so we are always trying to combat the smells. The pellets break down in a saw dust once they get wet and absorb liquid kinda like cat litter. You can spot clean and scoop out the clumps a few times a day. And again it's cheap, maybe 5 dollars or so per 40lb bag. It's not as much as pine shavings in a bag, but once they get older, it lasts longer. i change the pellets near their food/water the most often, maybe 1-2 times a week... but in their main living area and nest box, i change that every 4-6 weeks. I don't like shavings because my duck ming mei had to have surgery on her foot when pine shavings gave her a scratch and it got infected from walking on the poop sitting on top of the shavings. the saw dust pellets break down into is soft and does not hurt their feet at all. they'll root around in it, but they don't eat it.