How quickly does a broody hen kick out the chicks

[LuciferRoo]

Three weeks later and the chicks had been kicked to the curb by mama hen.
They still sleep in the same coop, but spend the days separately from the 3 adults.
Mama hen is somewhat mean to them, but she's never been that nice to other chickens.
The rooster and the other adult hen are just fine with them.
At night she does try to discourage the chicks from going into the coop.

 

[Perris]

My August clutch are just now drifting away from their broody, and the September clutch are still with their broody. They free range dawn till dusk, so maybe the broodies feel the need to be more protective or proactive for longer than birds in confinement might.

They are also hatched and raised with the flock, so there are no integration issues. Indeed, the 18 wk old cockerel is still being allowed to eat next to his dad, the dominant roo. The youngster has the good sense to have not started crowing yet.