I think 1-2 days, but she isn't always on her nest, so I'm not probably not gonna give her anything.......I have had a super mean easter egger who would not let me or other chickens NEAR her nest. The only time i hatched under a broody was when a lavender orpington hatched 1 chick and she pecked it's head open right after hatching

. We brought it inside and it ended up passing away the next day. The second time was a super sweet black australorp, who successfully hatched out 3 little chicks, and they are 12 wks old now. But i hope to hatch with another broody hen soon!