OK, this is what I do now -
I have a roofed breezeway. Added horizontal supports spaced 30" apart, attached bunny cages to it. Set a 1x2 on top, used left over metal roofing and plastic roofing to cover the bottom cages. Repeated above. Gives me two levels of bunny cages, its about 12' long, so I have room for big cages (I have Continentals and NZ Whites) - the smallest cage is 30"x30", they can't drop pellets on one another, pee on one another, spill feed or water on one another.
The bottom row is far enough off the ground I don't have to bend much, and I can get a shovel under it w/ (relative) comfort to harvest bunny gold for the gardens.
What I learned from this:
1) I thought the plastic roofing panels would be brittle in our high heat then breif freezes. That may be - but bunny urine is so acidic the metal roofing is sheeting and rusting. Frequent cleaning (see the hose?) helps, a lot - but its no perfect solution. The plastic panels turned out to be the better option.
2) Because we get wind blown rains at a steep angle, and because the bunnies are too big (and the cages too small) to put individual houses in them, I had to put partial walls on either side of the run. It allows wind above and below for airflow, plus the breezeway itself (our highs are just under 100, but our summer average is closer to 95) - but it still gets pretty warm in there. When we freeze, it gets cold. That's just the way it is. They tolerate both.
3) the chickens will scratch around in the bunny gold for missed pellets, bugs - the bunnies don't (usually) drop much. But by feeding them inside elevated cages, the birds can't get the feed.
4) having cover on the roof of each cage also keeps the mice and rat droppings out. That's great - because even with the chickens getting what the rabbits drop, its a rat magnet. I keep reusable (enclosed) rat snap traps on both levels, often baited with bunny food to help control the population.
5) when its hot, a continental can drink half a plastic coffee can worth of water in a day. I fill the plastic can each day to the top. Sometimes, the bunnies will chew the cans - it won't hurt them, but you will find thin shavings of red or blue or black plastic on the ground (depending on coffee brand). We don't get cold enough, long enough, that freezing has been a problem except one day last year. When the ice is thin, the bunnies go right thru it.
6) I also have metal feed bowls (blue and pink) screwed to the cage wall. Those feed bowls had stainless steel bowls inside them. When a bunny is playful, or mischeiveous, or annoyed, or bored, it will grab the lip of that tiny bowl with its teeth, flip it over, bash the cage with it like a prisoner with a metal cup in the old movies, then dump it in their water bowl. They can't be broken of the habit, so just remove the metal inserts. Use them for something else.
7) baby bunnies really will try and wedge their heads between the slats. they can even get them caught in 1x1" hardware cloth (and smaller hardware cloth uses such thin wire the cage deforms under their weight). Pick a breeder cage or two, use untreated 1x6 lumber, make a skirt around the base of the cage. use scraps as sothemth to screw into for the corners. Not only does it keep the babbies in and provide something solid for momma to start packing fur against, but your rabbits can also use it to keep their paws and teeth trimmed. I will place a few boards on the floor of the momma cage as well to keep the fur from falling thru and protect the babies from cold drafts from underneath. Remove as soon as they aren't needed, or your rabbits may start piling pooh on them - not something you want to clean.
