I don`t have sure it is fully implemented yet, but when you leave two pokemons at DayCare, when talking to the old guy, he says something that shows you approximaly how long those pokemons will took to make an egg. Here are the texts.
If you talk to the day care man, he'll tell you.
The two are friendly---It won't take many steps to get and egg
The two seem to get along---It will take quite a few steps to get an egg
The two don't seem to like each other---It will take a while to get an egg
The two prefer to play with other Pokemon than each other---There will be no egg
If you talk to the day care man, he'll tell you.
The two are friendly---It won't take many steps to get and egg
The two seem to get along---It will take quite a few steps to get an egg
The two don't seem to like each other---It will take a while to get an egg
The two prefer to play with other Pokemon than each other---There will be no egg