Rabbits can die in hot hutches.
Create shade if needs be but don't cover over, to do so you need air flow. Dampen rabbits ears with cool water, you can use cage fans too for air flow and bring them in if you need - give cucumber and bowls of water 
-not hot metal spouts on water bottles.Did you get a snuggle safe in winter?? Take off the cover put it in freezer... now you have an ice pod also put iced bottles of water in they can lie next to if they choose.
Our bun is chilled under the trampoline shade on cool earth with a bowl of water and fresh grass which was watered earlier for her so its wet for added moisture. She seems content and she has an aviary for night time which has great air flow. And her ice pod is in there if she wants it x