After laying her last egg, I only feed the hen her regular wheat germ oil blend coated seeds and a dish of hemp hearts along with water. Seems the hemp hearts encourages her to maintain a good incubation temperature and be content sittiing all day even without a male in her cage. She should not be feed greens or egg containing nestling food during sitting.
Hemp Hearts, a product from Alberta Canada, is sold for human consumption and available at my health food store. Since they are hulled hearts and won't sprout, they are not inactivated in any way. Sitting hens eat very little overall but they do eat some hemp hearts!
As I started to sit down for breakfast this morning, Lucca had a different idea!