There are lots of tips on here about keeping the birds cool. Most birds tolerate cold better than hot. The important thing is good ventilation and that they are kept dry and draft free. It's important to monitor your birds behavior. If they are huddled together and shivering, they are probably cold. If they are spread out and panting, they are too hot. If they are spread out and happily going about their merry selves, they are probably doing fine. Some people freeze milk jugs and keep them in the run so the birds can huddle around them to cool off. Fans, fresh water, shade, and even insulation can help with keeping temperatures down. If all else fails, you can bring them indoors (ie, basement or garage.)