@Beekissed, it's good to "see" you. @iwiw60 you too! I've been bouncing all over these threads. LOL
On the subject of sand: I had a run that once the girls destroyed the grass they left me with a muddy mess of clay so i put a layer of sand on top thinking it would mix in. Nope, and it made it even harder after the first rain in an uncovered run. I tried straw, just got stinkier. I raked all that out and put down equine pellets. It was like a miracle. I haven't had to do anything to the now covered run all winter. As the pellets get wet, they poof up into sawdust like crumbs. They love "bathing" in it. Now that spring is here, I'm cleaning out the coop this weekend and putting a mix of pine shavings and equine pellets in there too.
As for onions, I think the taste transfer is the big thing, not necessarily that it would hurt them although I avoid certain things anyway.