what is good litter (etc) for under a wire floor hutch?

i'm going to be building a hutch/house for my duckies and was thinking of having a wire bottom (the small squares so not uncomfortable) so poo will fall through and not stay in the hutch. the entire hutch will be raised off the ground with a tray or something under it that can be pulled out to clean so my yard doesn't stink my question is what is a good bedding etc that i can put under the hutch that will make cleaning easier and keep the smell down?