Have you tried gently palpating her to find out if there are any more eggs inside her?

It's not as easy to feel as follicles because the eggs are a lott squishier and pliant once the egg while and shell surrounds them but even a photo of her from above might help judge if there are any more inside her. Did you palpate/ ultrasound for an egg count previously?

Your vet will rpobably do these things but if you previously palpated 6 follicles and only one has been laid then this will help the vet decide on the time he has before any invasive procedures.