You know if we take the shell-coating thing in the direction that Homeless is suggesting, within a very few generations we will come to the point where eminems are 100% coating and 0% chocolate. Which will sort of defeat the purpose of their being the chocolate that melts in your mouth and not in your hand. And they'll probably break your teeth, as well.

I think that, instead of going for overall hardness, the breeding program should go for a specificed amount of hardness, and any more or less hardness would be bred out. This should be based on a scientifically derived determination of the optimum coating-to-chocolate ratio. Just enough coating to keep it from melting, or from breaking just when you pick it up, yet not so much coating that the chocolate flavor (such as it is, of course) is overwhelmed. Eventually, as the result of our new and improved breeding programme, the entire herd would be of roughly the same hardness.

Alex