egg stuck half way iut

How long does it take f or the egg to come all the way out. She had it half to 3/4 the way out for 5 hours and finally I gently helped her finish, She didn't seem to want to walk before she had it and spent the last couple days just swimming in the pond. Today she's near the pond and working on laying another. It's my first experience with geese laying eggs. right now she's laying the eggs on the ground. Should I build her a nest, if so what should it look like and be made of. Akso should I be feeding her anything special. She get's a grain mix and greens. Could I grind up oyster shells to give her more calcium. I'm way down in Mexico off the beaten path so the vets are all large animal vets. Thanks