older pullets quit roosting

[KLC321]

3 of my pullets started spending the night in nesting boxes. They are over 2 years old and have previously used the roosts. They have 3 different roosts.

 

[sourland]

Are they molting? Have you checked the roosts for red mites in the evening?

 

[Tired old Rooster]

3 of my pullets started spending the night in nesting boxes. They are over 2 years old and have previously used the roosts. They have 3 different roosts.

They are not pullets anymore, they are hens. Are they perhaps broody?

 

[Not-so Slick Chicken]

Has anything changed in the coop? Air blowing on the roosts? Leaky roof or water blowing in? Mice?
Has their flock order changed?

Pullet = female chicken under 1 year of age
Hen = 1+ year old
Cockerel = male chicken under 1 year
Rooster = 1+ year old