Are they true "Hens and Chicks" (Sempervivum sp)? Usually, the red color comes from sun exposure or sometimes from temperature changes in the fall. Like their succulent cousins, they change with the season depending where you live. Here in Michigan winter causes all of my Echeveria to turn green.

Depends on the variety, but more sun should redden.
In CT, Mine will get color, but not bright red or fully colored.