those little sheds get very stuffy, it helps to given them some air by eather having a secoundry mesh door so you can leave the main door open, you could also mesh the window, and i have a pipe leading ouside to a mesh run full of soil for them to dig in, that sort of cools them down i think as they only start digging and lieing on the mud when its hot. but i lost one of my jills in the heat befoure i made these changes.