The main thing to remember is that whatever method you use, you need to contain the manure at least once a week, especially in warmer months, when flies are out. This is because the life cycle of a fly is as little as 8 days from egg to adult (blow flies are only 143 hours, which is just over 5 days). If you don't keep ahead of them, you'll have a lot of flies, which increases your risk for fly strike.
Besides flies, it's still important to keep the area clean in order to keep ammonia levels down. Anyone who's ever kept a rabbit inside their home knows just how quickly ammonia smells can build up in just a few days. Ammonia can cause respiratory issues with rabbits, besides just being unpleasant to be around. It takes me about three days to notice ammonia smells from my house rabbit's cage, which has ammonia-locking cat litter in the tray. So unless you have an extremely well-ventilated area and very porous flooring (e.g., well-drained dirt), you'll want to clean up just to keep ammonia down.
For people who have cages that are allowed to drop directly on the floor, or dirt, things are a fair bit more simple than for people who have to deal with trays or stacked cages. If you have single-tier cages with plenty of clearance underneath, it's as simple as shoveling it out into a container or delivery vessel (e.g., wheelbarrow). In the past, I've dumped directly on the garden, dumped into a wheelbarrow or wagon and dumped that into the garden. Currently, I shovel everything into feedbags, which I can then sell, give away, or use in my own garden.
|Shoveling manure into feed bag.|
|Using back of rake to scrape under cages.|
tier stacks, and while the bottom level doesn't have tray, it has a rather low clearance below the bottom cage (maybe six inches). I've found that the most practical method for getting everything cleaned out from under the bottom cage is to use a short-handled, flat-backed garden rake. I could probably use a short-handled hoe, but I don't have one, and I find that the tines on the rake are handy for breaking up piles. Once I have everything scraped out from under the cage, I can shovel the pile into a feed bag (or wheelbarrow).
|Plywood floor under cage after scraping.|
No matter how well you scrape, you'll never get everything off the floor, but you can get close. If you really want to get clean, you'd probably have to use a scrub brush with soap, water, and maybe a little CLR to get rid of the calcium. Who wants to do that? Just remember that the floor will never be the same after you've kept rabbits on it.
|Square-nosed shovel fits squarely into trays.|
|Tray that's never been dumped--|
only scraped clean with a shovel--
since it was purchased a year ago.
Notice it still has some galvanizing.
|Pile of manure in back corner of tray.|
|Rotated tray so that the pile came out first.|
|Sprinkling stall freshener on tray.|
These are by no means the only ways to do things for rabbit waste management, but it's what works for me.