I'm on my second set of ducklings brooded and hatched by their mothers (actually 5 hatchings come to think of it). I give the Ducks hay to make their nests that are on the floor of their Duck House. The Food area and Roost Area (not much used) are covered in pine shavings with 1/2" wire under. There has not been a problem. The mothers keep them in the nest the first 3 days than take them to water and food and then have them walk around on the shavings. The smallest ones usually go to the food on Moms back then slide down to join the others. The shavings are much easier to clean up than the hay. Though when they get to be adolescents, that starts getting messed up. Depending on the weather at hatching time, by day 5 or 6 the Mom's take them outside into their enclosed Run, which has hay spread on it. This last group, they have only just today ( at 2 weeks old) taken them out into the yard with the 12 week olds.