The first time Enzo laid eggs, on the second day she plucked all of her belly in minutes, I was heart broken for her. She stopped at this point though. I took her to the vet once her 4 eggs arrived and the vet was very interested but not concerned about the plucking, he believed it does happen occationally and especially when a bird lays her first batch.
As for the eggs cracking, im not sure as Enzo's eggs have fallen 6 foot to the ground at times and not broken, but they fall on to a soft matt that I place under her to catch her droppings, other times she lays her eggs when she is in my arms so no impact at all. What im saying is, if the eggs fell on to bars at the bottom of the cage, I doubt any egg, soft or not would survive that impact.
I believe its normal for 4 eggs to arrive, with a day or three between each egg, although last month Enzo only laid two. I would keep a very close eye on her and try not get her too active but instead comfortable and calm. Her hormones will be all over the place and no doubt she is acting very differently at present, maybe looking for dark corners, less interested in being close to you and your family. This will pass.
I do however agree with the above sentiments and increase her calcium levels, you can buy avain calcium powder, cuttle fish, mineral blocks etc etc, Enzo loves natural unsweetened youghurt with little pieces of fresh fruit, not too good for her but in small servings (1 level teaspoon tsp) I think harmless.
Id also call your avian vet if not local and explain what you are seeing and allow him to decide if a call is necessary or not.
I hope this helps you and your little grey hen, and congratulations n your close bond with the bird
