Actually, it was another member who said 'bursting'. I said cracking, and I know the difference. Eggs do crack sometimes during the cooking process. It's a fact of life, although, as has been pointed out, using the correct size pan and a gentler boil, will help prevent this from happening. And eggs that have been on the shelf for a few extra days will be easier to shell.
To answer another question, water entering the shell has no affect on the quality of the egg. It's not that much water in the first place. The hole actually amounts to harly more than a pin prick. Also, there is a protective membrane inside the shell that helps to keep the water from coming into contact with the egg, if the egg is properly pierced...this is the reason for piercing the fat end of the egg, where there is an air pocket.
As I said before, it is not necessary to pierce eggs prior to hard cooking. This is not a 'right thing' vs. a 'wrong thing', just a matter of preferrence.
