Mine are in a north facing room that doesn't often get hot. About twice a year I may have to put a clothes horse of wet washing in the room during the hottest part of the day but that's rare. The clothes horse has come in from the shed and water bottles are in the freezer just in case. Other than not going out in the garden runs until evening and not having fleece tunnels or beds in the cages we haven't done anything different so far. It's been very overcast here for the last few days so the temperatures have not got as high as predicted, fingers crossed tomorrow is the same!