Idunno. I use pine shavings and leave the food they scatter in the brooder. They will scratch around looking in the shavings for the food. I guess it is rewarding their innate behavior. In any event, I just leave it there. I also leave the poo. I add more shavings on top. No smell. When I get ready for new chicks, I will clean out everything and start fresh.
Me, three. I use those long rectangular feeders with the spots for them to stick their heads in. And like Donrae, I elevate the feeder a bit by putting it on a chunk of concrete I poured just to use in the brooder. About 2" high. I have a round one that I use to put the waterer on as well, so the water doesn't spill.
I have found that my chickies smell if they get too crowded. Is that perhaps the case with you?