My RIR, approx. 16 weeks old, was acting weird last night. All the other hens were standing around and she just plopped down on the grass. I went out to her, she didn't get up. Just sat there. Went out at dusk to make sure they were all on the roosts and she was up with the other ones. Is she getting ready to lay? I'm a newbie and am not sure what signs to look for before laying starts. I have 1 RIR hen, 1 RIR rooster, 1 Buff orpington, 2 Silver-laced Wyandottes and a Black Autralarps.