Single post in "Adopt six" button in the Daycare

That's true. For variant hunters, this button is probably going to be more complicated. Maybe it could be something like once you click the button, if there are more than one type of egg in the daycare, it would ask you which eggs you want to adopt (which has a toggleable option of saving a cookie). For variant hunters it may not save as much clicks as it would for those who have breeding pairs only producing one type of egg. For a select amount button, it would be essentially the same thing, just with a number to type (and another extra toggleable cookie). And if there are no other eggs, it will just adopt eggs without question (unless the button is turned off in options or something).