It is very usual for a broody hen to get pale in the face while she is sitting on eggs. The chances are, the hen is not getting up and walking around while you are there because she doesn't feel safe around you. This is usual even for the most trusting broody mother. Most likely the hen is getting up and eating and drinking when you are not in the coop. The mother would be forced to poo in her nest if you are hanging around the coop and the mother to often. The mother uses the times when she feels safe to get up, stretch her legs, poo, eat and drink. Leave the mother alone for a little bit and place food and water a little ways from the nest. Don't put the feed where she can reach it from her nest. Make sure the coop is very secure and has no holes or openings or drafts, so the hen feels safe to leave her nest when you are not around. Check the hen for any injuries if you really think that she is not leaving the nest even when you are not around. After a couple of days, trash the eggs and let the hen mother the born chicks properly.