I'll start with apologizing if this is already been discussed 100 times. My husband and I are new to raising chicks and in light of a new article it's raised a couple questions. My fingers crossed girls are approximately six weeks and are pretty close to being fully feathered (not much fluff left). What age can we stop using the heating light? They are still in their brooder which is in our converted heated garage (60-70 degrees). Thank you for any help!