Help - one of our six 3-week old chickens died today. I was gone for a week while my husband and kids cared for the chicks, who seemed to be fine but getting crowded in their brooder box. They had been taking them outside for little jaunts. Today was a nice day and we were going to be working outside to get the yard ready for their coop, so I thought they would be fine outside for 3+ hours. They were all running around for awhile and then seemed to rest for a bit in some shade. We cleaned out their box and put them inside (without the lamp for the first time) for a few hours, and when we came back one of the chicks was dead. She seemed maybe the smallest of the bunch but not a complete runt at all. Perhaps she got dehydrated? Outside temps were in the high seventies in the sun, maybe higher. In the shade it was cool. When we put her back in the brooder box she seemed to be breathing heavily but I just thought they were exhausted from their outside romp. I'm worried that maybe she caught some disease that will spread to the others? I'm a newbie at this and was so sad that one of the chicks died New Chick Mama of now 5 chicks.