Heby, they may be running out of room. I built a 4x4 brooder box out of clearance sale plywood pieces at Lowe's for less than $23. Look around your local home improvement stores and see if you can find some of what I lucked into - our brooder is sturdy and will last a looooooong time with plenty of room for up to 35-ish full-size fowl chicks to make it to the 6 week mark. ;-)
If you have a dog kennel, that works awesome as a temporary outdoor safe-space - just take the tray out of the bottom so the grass comes through, give them a bowl of chick grit, and let the games begin! They love warm days and fresh treats even as young as a week old