It is all about the Roost! size matter?

[harmonyp]

They "tend" to go for the highest available spots, so if your nest boxes are higher than your roosts, that's where they'll go.

 

[Bigbluefrog]

The roost is higher,

also noticed the pullets all go to left side of the perch!

I read somewhere that one did a study on roosts and his hens preferred the left side too.