I thought it would be worthwhile to see what Harold McGee has to say about
this favorite topic. This is from the new edition of "On Food and Cooking"

Cracking: usually caused by the eggs being knocked about due to too-fast
boiling water. Poking a hole in the end of the egg does not help.

Tough whites: Caused by too-hot cooking temp. Best to cook in barely
simmering water which is 10-20 degrees cooler than actively boiling water.

Hard to peel: usually caused by really fresh eggs. If you have only fresh
eggs, add 1/2 tsp baking soda to 1 qt cooking water. This can help.

Green yolks: more prevalent with older eggs. Over cooking, cooking at too
high a temp, and not cooling rapidly also contribute.


--
Peter Aitken

Remove the crap from my email address before using.