I just got my step mothers 3 chicks that are about 5 or 6 weeks old. One barred rock and 2 red something or others. I live in Phoenix and I worry about using a heat lamp outside. Do I stillstill need to use one at this age? Ours highs right now are in the 80's and lows in the 40's to 50's. Usually 50's. Being Phoenix I built the coop to stay cool not warm. Also whatv about vaccines? They had medicated starter food. When can they eat mostly scraps? Anything else I should know? Thanks in advance!