Would chicken sit on eggs after laying dozen and do you have to pick up the put them back?

Chickens will absolutely sit on eggs after laying a dozen! They are natural mothers and have an instinct to incubate their eggs.

However, it's important to understand a couple of things:

* Broodiness: Not all chickens become broody. It's a hormonal response, and some hens are more prone to it than others.

* Broodiness and egg production: When a hen goes broody, she will stop laying eggs. This is normal.

* Incubation: If you don't want chicks, you need to break up the hen's broodiness. This can be done by:

* Removing her from the nest: Place her in a separate coop or run, away from the eggs, for a few days.

* Disturbing the nest: Remove the eggs and replace them with fake ones, or cool them down with cold water.

* Light and exercise: Ensure she's getting plenty of light and exercise.

* Diet: Limit her access to food and water, though not excessively.

It's not necessary to put the eggs back unless you're trying to encourage the hen to incubate them.

If you don't want chicks, you can collect the eggs regularly to prevent the hen from becoming broody in the first place.