So I am completely new to this chicken raising thing. Got my first batch a little over a week ago. I have them in a brooder in my laundry room temp sits right about 90 in there. Every one seems healthy eating drinking pooping well. Yesterday I took them outside and let them run around in a 4 by 6 foot box with no bottom wile I cleaned out the cage. They were out there about 20 min. Every one seemed fine. They went back inside. Later that night I checked on them and the smallest one was dead? I want to make sure I don't kill off any more of I can help it so I'm trying to figure out what happened. Did he eat something he shouldn't have did he choke on something? Should I not let them outside for short periods of time yet?