I just mailed 5 small white plastic eggs to a friend of mine who has 5 lovebirds. The females are laying eggs and my friend keeps taking them away because they don't want baby lovies. So I explained to her, why she oughtn't do this and picked up 5 eggs at the FWCAS meeting to send to her so she could just swap them out instead.
I also suggested that she cover her cages with a dark cloth at night for 10-12 hours so it is never Spring. Don't know if it will work for her lovies but it sure work's for my tiels and Fiona. Four years and no eggs!
Actually, it's not good for birds not to have a breeding season ever so, although the practice of keeping them to less than 12 hours of daylight throughout the year would prevent them from going into breeding condition, in my personal opinion, one should not mess around with the endocrine system that much.