How hot is it inside the garage? Some garages heat up as it gets hot outside and some keep cool. If I were you, I’d grab a few thermometers, put one on the middle-ish of the garage, one in the “hot corner” of the brooder and one in the “cold corner” of the brooder. If the brooder is under 95 degrees in the “hot corner” and above 75 degrees in the “cold corner” I’d say you’re fine as. As long as only one corner is getting the heat, chicks can move about to find their ideal temperature. Hope this helped!