We are in Texas, and the temps have been pretty warm until the past few days. We've experienced a range from 60s (night) to 80s (day).....and it recently has topped in the 50s with an expected temp of 36 this evening. -chicks have been in their outdoor coop since about 4 weeks of age. We've actually had fans on them in the daytime due to heat. Our coop is only enclosed on two sides with hardware cloth on two sides. Is a heat lamp necessary????? -only concerned because of the sudden/significant change.