It must be the water, lol!
This hen has been a problem child for the past month. She was raised in the eggers coop but decided for whatever reason that she liked the Silver Pencil Rock rooster in another pen. She constantly managed to get out of the eggers paddock (which is surrounded by an 8 ft chain link fence), walk over an elevated board to the edge of that run, fly across the silkie's run to the roof of the other coop and then jump down into the pencil's paddock. We kept finding her cuddled up to the other rooster in the evenings and DH finally caught her in the act and watched her. He caught her and returned her to the eggers paddock and she promptly repeated her escape route. So for the past 3 weeks I have had to mark SPR eggs as questionable since she lays brown eggs like they do!

Her brooding will resolve the egg identity problem for a while at least!