I have heard that you can store them for about 7 days as long as you angle the box they are in from one side to the other (basically lift up the corner with a book underneath and at evening move the book to the other side. I have started doing this because it is so much simpler to remember that you put the eggs in on Saturday evening and they need to come out and they need to come out 3 weeks from Wednesday to go in the brooder to hatch on Friday evening/Saturday morning!!!! Also if you are doing this once a week, on Wed you remove the earliest date of eggs.
WARNING WARNING WARNING!!! You can put them in 3 at a time but you loose track of which one needs to come out and when. Even when you think you are good,
if you know what I mean, you forget to write the date in pencil when you put them in and there goes the plan. TRUST ME, BEEN THERE DOING THAT AT THIS PRECISE MOMENT. Needless to say, I have woken up 2 different days this week with a little fluffy butt
sitting in an egg cup waiting patiently, chirping loudly, saying let me out of here,
wondering where the heck he is, when he/she should have been in the brooder waiting for hatching. There is no harm to them if this happens but there COULD be if they get stuck in between the turner arms.
If you don't have a turner, take my word and GET one, makes a world of difference on hatching rate.
Good luck and happy hatching! This is one of the most fun things you can do!