Keeping rabbits cool in extreme heat

what you see is two rows of cages with 20 lb bags of ice between them. Covered with a large drop cloth and moving blankets. The ice last more than a day, and it is cool and dark for the rabbits. Much like being in a burrow. We do this when the temperature is above 90° , and we put them back on the rack in the evening.

The temperature range here in N.E. Arizona is pretty extreme.
While we have plenty of wildlife that seems to do just fine on both ends of the spectrum, I felt it necessary to install heat & AC in our barn.
That was for the horses but since our rabbits moved in, they can benefit from it too without added expense.
For my own sanity, I haven't calculated the monthly cost of that but for most I suspect it's prohibitive.
Temperature in the barn stays between 70-74 degrees year round.
Due to the fact that we have extremely low humidity here in the desert, evaporative coolers are quite efficient and relatively inexpensive to operate.
I take full advantage of that during the summer months by leaving the evaporative coolers running 24/7, then supplementing that with conventional AC on a thermostat.

You can provide them with a shallow pan of water. They might lay in it or walk in it, or just dip their paws in it if they need to. Some rabbits like water and will go for a swim if given the chance.

We started our rabbits in an insulated enclosed metal barn with a portable AC. We left the door up until the temps hit the 80s and the inside no longer benefited from outside airflow. Then we used the portable AC until outside temps hit 90. At that point it couldn't keep up, so we started adding the ice water bottles. But when inside temps began to hit 82-83, we ended up moving then entire set up into our heated and cooled garage. That worked great until the Fall, which by then we were about being run out of the house due to the odor. So, we had a problem to solve, as we just could not do this every year. One issue I could not understand was why the portable AC (the kind that sits on the floor on wheels and has a hose that runs out a window) could not keep the barn cool. It was supposed to be plenty big enough, but it just wasn't cutting it. I began to research larger units, and it was through my research I discovered that portable ACs with a single hose create a vacuum in the space being cooled, thus pulling in air from any openings. Normally, if you used one of these in a warmer part of your house, that would be ok because while it is cooling, it is also drawing in cooler air (because of the vacuum) from the other cooler areas of your house. But in a shed or barn, it is just going to replace the warm air it expels with warm air it draws in, while also expelling some of the cooler air it creates. So, there are dual duct units that are supposed to not create the vacuum, but these are about as expensive as normal window ACs. So, long story short, I installed a window AC rated for space twice the size of my rabbit barn. We will see how it works once we hit June, July, August weather.

We have our rabbit cages in a hoop-house under mature oak trees. It is protected from the North by a six foot privacy fence. The doors are on the East and West sides and the fence funnels the summer breeze right thru the doors. In the summer I put 12"X18" ceramic tiles in the cages with a frozen gallon jug of water at the end. The cold from the jug cools the tile and the rabbits lay on the tile next to the water jug. I'll turn a fan on to circulate the air if there's no breeze. That keeps them fairly comfortable even in the 90-ish temps we get in July-August. A larger rabbitry would probably need a freezer dedicated to jugs of water.