Not to change the direction of this thread but what aart says about sand makes a lot of sense. I use sand in my poop trays under the roosts. If aart would be so kind to give input on this I would appreciate it. Should the poop trays be used at all? I do the deep liter in the rest of the coop. My coop is more of an open air coop with 3 walls and hardware cloth for the fourth wall. Sorry about hijacking if I did....I'd go for the 'deep litter' rather than more sand.
I used sand as a brooder bedding, which worked great for daily cleanups, but eventually the sand become saturated with pulverized feces and you can't separate them or clean it. The sand was good for nothing but filling some holes in the front yard from an auto accident.
Sand can help with drainage but it can also hold moisture, as you've found.
When it comes to chicken poop, moist equals stink.
The DL can also hold water but will also support a microbial population to 'eat' the feces that sand can't.
If you do decide to try the 'side by side' comparison, better put a tall(~12") barrier between the 2 as the chooks will fling one side onto the other.....
......or you can evaluate the 3rd option of a mix between the two materials.
Best of cLuck to ya, looking forward to hearing about how it works out for you.
Marie