My chicks are about 4 1/2 weeks old. They will be being moved to a rabbit hutch that has been converted into a chicken hut. There will be pine shavings on the floor and and "house" that is fully enclosed the "run" part of it is enclosed on 2 of 4 sides. It will be inside a barn, the tack area part of it. We have access to electric, but prefer not to use a lamp if it isn't needed. It has been getting down to about 30F here at night. They are Mixed Laying chickens (LF) and Guinea Keets. Would they we Ok with out a heat lamp? What about Silkie/Showgirl (10 total) Chicks the same age? The house is about 1'X1.5', the run is about 1.5'X3' The LF chicks and Guineas will be in the same hutch, and the Showgirl/Silkie Chicks will be in the same hutch, but not w/ the LF and guineas.