What breed are you hatching? I'm completely new to hatching goslings but I did read they usually hatch between 28-30 days. I'm hatching a mixed breed so I'm doing lockdown on day 25 and I read that it's normal for goslings to take up to 3 days to hatch once they start. It takes them much longer than chicks. Since you have one that is almost out I would wait until it's done hatching and give it some time to fluff up in the incubator and then you can candle the other two if they still haven't pipped "externally" through the shell, to see if they have pipped "internally" through the membrane yet and see if there is still movement. Let us know how it's going!