Chicks range from about 1.5 wks to 3 weeks old- should I switch to a reptile lamp or take away heat?

[Chickadooo]

Im in Michigan and the weather will be in the high 60's during the day and low 50's at night. My chicks are in a big box brooder in my insulated garage, no drafts and it generally stays pretty warm in there. Being that I have chicks that range from 1.5-3 weeks old, Im not sure what to do with the heat situation. I've been keeping a heat lamp but not shining directly into the box, so it stays at about 82 degrees on the warmest side and about 75 on the cooler side. I cant seem to find any info on taking heat away at this age.. i think the older birds who definitely have more feathers would be fine but Im worried about the smaller ones. ***I wanted them to get use to sleeping in the dark*** so maybe I should switch to a reptile lamp or no lamp at all and they can huddle together for warmth? Any tips please? New here, so please be patient with all my crazy questions!!!

 

[Dmontgomery]

The chicks usually need heat for about 4 weeks until they “ feather out”. Since that is going to be different times for yours, you can set up a second brooder for the older ones or, if your current set up is big enough, separate the brooder in half. Put cover of some type over one side. It will be slightly cooler in the shady area. That way the bigger ones can cool off while the smaller ones can stay under the heat lamp if needed.