First year for meat birds, started with 20 and I am now down to 11. They are around 5 lbs, around 7 to 8 weeks. The past week I have been losing one about every other day. I have them in an outdoor pen about 5' by 20' in northern Michigan with a shelter they can go under to get out of the rain, however all of them don't. Well shaded area. I always find the dead ones in the open. Today I found one that seemed alert but just couldn't really move anything other that its head and neck, plus 2 dead. Yesterday they all seemed fine but we had a heavy thunderstorm last night with a cold front but I'm sure it didn't get under the 40's. There has been no weather issues with the previous ones that died. Feeding them grower/finisher food 20%.