When they have this happen it's very hard for them to lay the egg, and it can make them feel unwell. I would probably go ahead and give her a calcium supplement for a few days, hopefully that will help and this will just be a glitch. Do they have access to oyster shell always as a calcium supplement? The needs can vary a lot from bird to bird and some will need more, some will need less. This time of year, as many birds come back into lay this can be a bit more common as their systems get spun back up. It can sometimes be an indication of a reproductive problem, but at one year old, hopefully that is not the case and it's just a glitch.
