How do you know they're getting ready to lay?

[LeahOregon]

I read in a post that someone's hen was "acting ready" to lay. What does this mean?

Today while my white rock was in the nexting box getting ready to pop an egg, my red star, who hasn't layed yet, went in the other box and started singing the same egg song. No egg, though. Does this mean she's getting ready? Her comb isn't very developed yet, and I thought that was one of the main indicators of laying readiness.

 

[Tiramisu]

Maybe they meant squatting? Or it could be some of the things you said. Just any normal chicken antics that show they are ready to lay.