starting my first set of incubating eggs

[shan04]

So I'm new to this hatching eggs thing, last year was my first time and 1 hen succesfully hatched 13 out of 13 on her own, this year she decided to stop sitting when they eggs only have 3 or 4 days left, so I took them and her crated her in hopes they are ok and will still hatch. I checked on them last night and she was still sitting but when I went out early afternoon today She was out and about and the eggs were cold. After that experience I've decided to start incubating myself.
What I'm wondering is I know I should store them no longer than 7 days before incubating can I collect what I can in that 7 days put them in the incubator then within the next 7 days collect what I can again and add them to the previous batch in the incubator? It would still be before lock down time.