In reply to:

e.g. flickers I saw a site that said when eggs were removed right after they were laid,
a female flicker laid over seventy eggs!

What's the time frame here?

Just an aside:

My Aunt Jewel has a lot of bluebird boxes on her farm. One spring she cleaned out the boxes to ready them for the new nests. She came upon one box and removed a nest that she thought she'd already removed the previous year. Well, she was wrong. That poor Mama bluebird arrived at the box, and she was about ready to pop with the egg inside her. Seeing that her nest was gone, she just sat herself down on the floor of the box and laid the egg on the floor. Jewel really felt bad about her decision.