I didn't, but we have the Ecoglow, which you can't really test with a thermometer so I lowered it a bit and that seemed to help. We added a 3rd chick to the brooder who I thought was fluffed out, but after investigating her belly is matted in yolk (we had one that didn't make it). Should I clean that off? Leave it alone for a few days? I tried to wipe at it with a wet paper towel but it didn't make a difference. I'm also afraid that I"ll hurt her belly, the skin seems so thin.
Dont wipe off the chick.
It could be still absorbing the yolk or could be the umbilical cord remnants. Leave it and it should resolve on its own.
I don't recommend washing the chick.
The ecoglow or similar are nice, but they need to touch the top plate for radient heat. The top plate should be roughly 3" from the ground for standard chicks. If the chick is out chirping, gently push it under the brooder so it finds the heat. It should stop shortly after.
You mentioned that one was pecking the others. If it is pecking obsessively, it is a sure sign that it is likely too cold. I don't know why this is, but I have experienced that and the issue was that it was simply too cold. When it got warmed up, no more pecking the others.
You can also provide bottom heat somewhere else in the cage and I recommend it. They sell products that are chick heat mats. You can also use a seedling heat mat. Just make sure there are areas of the cage where they can avoid the heat it needed.
Warmth is critical. ambient temp should be 95 for first week, or adequate radiant heat. I always have two heat sources (radient, unless the chick is blind and in that case, IR heat lamps) as more often than not, one will fail and you will need the redundancy.
Good luck and hope the rest do well!