laying and hatching only happens in active area. Sleeping or time passing when you are far from the area does not progress this. Chicks growing into hens will happen if you sleep / go away. 30 minutes must be uninterrupted. If the fire goes out, if you pick one up, if you are remodeling and they briefly lose shelter - 30 minute timer must restart. An egg can be only "warm" or "too cold". Keep them warm for 30 minutes of someone being in the active area.