I don't know if they would eat kitty litter or not but I would NOT use it.
First - expensive
Second - it will absorb moisture from the humid Florida air.
Good plan with the removable roosts. I did that with the "perching roosts" in front of the nest boxes AFTER making my sleeping roosts non removable. I can rotate the two 3" fence rails since their smaller diameter ends go into holes but the 2x4 is fixed. I would have had to pin it since it keeps the brace on the open end in place but I wouldn't have to remove screws to take it off for cleaning. That said, I've not needed to clean the roosts.
How close to the wall is that lower roost? They may not like it if it is so close that their tails mash into it. But I bet they sleep on the higher roost anyway and the lower one will be a good staging level as they all jockey for position. My girls have been together since they were put in the shipping box in Texas to be airmailed here. You would THINK they would have it all figured out by now since they will be 2 years old in June but Noooooo, they have to piss and moan at each other every night (at least the one's I've been in the barn to witness the procedure) about who gets to sleep where and the Cubalayas shoving under other birds to get where they want. I'm surprised it is allowed since they are 2/3 the size of a standard large fowl, they are definitely NOT high in the order.
Looks like you've made some good changes. Let me know if your birds use the lowest roost when they are bigger than a couple of months. My understanding is they all want to be as high as they can get so your highest roost will have all the birds if they fit. If not, those lower in the pecking order (both references are literal when talking about chickens!) will be on the lower roost(s).
Bruce
