Mine generally take 30 days. They can take up to 3 days to hatch once they start pipping, too. We have made the mistake (with the incubator) to help them out if they seemed to be taking too long. It's really hard not to, but don't do it unless it's absolutely necessary. What we've learned the hard way is that thise are usually large goslings and it takes them longer to absorb all the yolk. If you help them out, they haven't had time for this process to occur and they often didn't make it or they had navel problems because the umbilical doesn't dry out sufficiently for them to break out without bleeding. If they're being incubated naturally, just keep an eye on things from a distance that's comfortable for Mama.