Chickens die when it rains

[Masterjoe]

So I have my cornish rocks in a covered chicken tractor. Have chicken wire for sides and corrugated tin roof. They been fine here almost 2 weeks. Birds are about 3 weeks old. We got an in of rain yesterday and at the end of the storm it was cooler outside obviously. I had 6 dead chickens. Today its 63 outside and by 12:00 I have 3 more dead. I'm not happy. Any suggestions or anyone else have this problem? This is not my first rodeo dealing with this issue. Need a fix. Thinking about laying 2 large tarps over it on cooler rainy days to keep it a bit warmer inside. I had 48 birds in a 14 ft 9 in by 8 ft tractor 24 inches high. I now have 37 chickens.

 

[Hope4Hennsyvania]

Im so sorry to hear that. Im not experienced with baby chicks yet, but everything ive read says they need to be kept 90‐100° first week and reducing by 5° each week, until about a month old. Maybe 63 degrees was just too cold?
My babies will be here in 2 weeks and the temp thing really has me nervous. I purchased heating pad and lamp, for the 1st month and planned to move them outsode after (it will be summer)
Have you noticed any of your other birds ill? Maybe something they ate?
Again sorry this happened to your chicks