How long can a chicken mother stay away from its baby chicken eggs for?

This depends on the surrounding temperature. If they have just been laid and it is at least below 60 degrees F, the eggs can be in a state of hibernation and will not start development until they are sat on, however, the longer they are left to sit the worse the chance for the babies. After the eggs are being incubated by the mother it is important that hey stay at a steady temperature otherwise there are likely to be developmental problems leading to dead babies. In general, the eggs can be left alone for about 30 minutes, however if it is very warm out this can be longer, but if cold it must be shorter. Keep access to food and water close to your mother chicken if you are worried that she is staying off her eggs too long. Also, if your chickens are accustomed to meeting you when you come up to the pen, keep visit short because they will leave the nest to visit if they expect treats.