Some females will try to compete in egg laying. If one lays, the other may very well try to match her. There are things you can do to prevent or reduce the likelyhood. If you are not wanting to breed separate them now before they get too attached. It's much harder to do it with a bonded pair.
If one of them does lay an egg as a single female, it won't be the last. She'll ussually have one every other day until she completes her clutch. NEVER take away the eggs until she's lost intrest. Doing so will cause her to drain her calcium supply by replacing them. She'll sit on them for about 2-3 weeks are realize their duds. At that time, and only then do you start removing them one by one. You'll know when the time is right.
Things you should do in the meantime are:
Provide 12 hours of dark *night time* to simulate winter (non breeding conditions)
Change around her cage location and cage items *perches, bowls, toys, etc*. This will take her a bit out of her comfort zone and bring her out of condition. You should do this about once or twice a month on a regular basis. It's also good idea to do it after you've removed the last egg.
Limit high fat/high sugar/high protein foods such as egg, seed, millet. Replace those items with healthy things like veggies, beans, etc. Be careful not to take away essential foods in her diet. The idea is not to deprive her, but to make sure food is not available in abudance. Calcium and D3 are very important during egg laying.
No petting on anywhere but her head. SO many owners make the mistake of rubbing their female's back and she ends up thinking you're her mate. Yes, she will try and lay eggs for you.
Do not provide any nesting material and remove any toys that she might be getting *frisky* with.
Don't let her go searching for dark spots-they're looking for nesting spots. *under couch pillows, book shelves, cupboards, etc*
All these things combined should bring her out of condition and lessen the chance of eggs.
