108°F is fine for pad surface temp, a hens body temp is ~106°F.
Key is being able to adjust height of pad to where chicks can touch their backs to pad.
1.5-2" in back and 3" in front is a good place to start.
Thanks Aart. I’ll keep it on high then. And it’s totally adjustable, I have carriage bolts for legs, and wing nuts to adjust the height.