I've been keeping my 3 week old chicks outside all day for the last 4 days now. It's in the 90's here. I've been bringing them back in each night but hope to have them out for good by next week, when nights should be in the upper 60's. I have my 9 chicks (3 standards, 6 banties) in a 4' x 8' portable run. They love it out there!