My sussex was put on antibiotics after being attacked by a possom, so we've had to throw out her eggs. Now it's not really smart but I tried to throw one of her eggs into the empty lot next to our house.. it went about 20 feet, landing on hard dirt and rolled down a rocky slope. Didn't even crack! I dropped my Easter egger's egg 2 inches from the countertop once and it cracked... Do different breeds have different shell quality? They have access to oyster shells but I don't think they all eat them.. I've often thought of supplementing calcium since one of the hens, a buff Orpington, has had a couple eggs break inside her which has led her to almost completely stop laying.... but I am dumbfounded by the fact that the sussex's egg didn't even break, shes obviously got enough of what she needs to make strong eggs, this is all while growing back all of her tail feathers! Can someone tell me more about this, or give me some links to read up on it?