I have the same problem with my gals, they all seem to want certain boxes. When a gal gets in her mind she wants something specific, you know it can be hard to change her mind! When they start loading up, I put fake eggs in other boxes and that helps them spread out some. I sometimes get 8 eggs in one box. I don't want that because there is more of a chance of breakage. So I put a few fake eggs in some other boxes and it usually works to get the gals to broaden their perspective.