How soon can you start the broody breaking process?

[JenFid]

So we have been using our broody jail with pretty good success...but I'm wondering how soon can you stick them in there once you start seeing broody behavior without them being "fully" broody yet? You know, the walking around flapping their wings and screaming randomly, puffing up like a turkey, the "wop wop wop" broody cluck, screaming when they're on the nest...but still actively laying and haven't yet committed to staying on the nest full time.
A couple times now when I thought a couple of ours were fully in it and have put them in jail (wire dog crate with the plastic bottom and a 2x4 to roost with a fan on them), they end up laying an egg, which makes me feel a little bad that they had to lay it in the crate! But sometimes it can be so hard to tell...do they want to go sit on a nest or do they need to lay an egg?
This happened with one of our Wyandottes just last week, so it got me wondering when the "best" time to put them jail is?

 

[D13]

I would say give them 2-3 days before locking them up. If it's broody, it will sit on the nest consistently. If it's just laying, it'll finish and move on.

It's normal for hens to act "broody" while laying, I have no idea why.

 

[rosemarythyme]

It can be hard to tell where the perfect cut off is if you have hens that have prolonged pre-broody periods. It's fine even if you jump the gun a tiny bit and the hen still has one last egg queued in her system. She'll simply have to lay it on the floor.

 

[ChookaPete]

During the "pre-broody" stage, the hen will do those behaviours you said, but is also eating a lot to build a store of fat to last her the broody period. So she still could be laying eggs.

It is not until a certain (and unknown to me) level of prolactin hormone has been reached, that makes her fixate on her nest and set into broodiness. How much and when that happens is different for every single hen. Basically if she has not left her nest for two days straight, and makes those broody noises whenever you or another chicken goes near her - she is BROODY!