hatching emergency

I am having a hatching emergency with my broody hen. I have an asil which was due 36 hours ago. One chick hatched and was found dead under the hen on day 19.one was found dead at a little distance from the hen...wasnt fluffed up.two hatched on day 21 end. One started pipping but lost steam before it could zip out... the membrane was hard and stuck. There are still a few under her and she is sitting tightly. Considering its about 48 hours over 21 days wonder if I should look forward to any more chicks or if there's a was to help get things moving along?