i have females doing that as well and they laid fine i have 1 that was total invert almost total head to tail and she laid 7 perfect eggs with no probs .
i dont see it being a sign of egg bound to many of them doing it and laying with no probs ..
dont freak out cause thats not gonna do anything but cause you to make mistakes and act with bad judgement . just keep an eye on the days and calculations , i think you should have no probs