I was using a heating lamp. The controller + lamp combo worked poorly. I used a heating pad for my seedlings, but it might work better than the lamp for the chicks in this setup. Good luck.
Just keep a close eye on the chicks for a while to verify they are comfortable as it turns on and off...
The point really is to make the chicks as comfortable as possible in the absence of a mother hen. I tried the same idea with my last brood (my 3rd) of chicks. It worked poorly and I gave it up after a couple of hours.
I have a similar thermostat+probe that I use in the spring when sprouting...
You don't really need a thermostat. The chicks are the thermostat. They will move closer or farther from the heater depending on how they feel. I put the heater towards one end of the brooder so that there is a warm end and a cool end.
Here is a simple way to judge their comfort:
-If they...