Actually, it's very easy. You give them good nests as soon as you see breeding behaviors. Then you check in them every morning and, when you find a new egg (every other day), you just replace it with a fake one. My lovebird is sitting on five eggs right now (her second clutch), I did not have fake ones in their size so I hardboiled them and put them back. She doesn't seem to know the difference (some birds do, though, and would throw them away after a few days but most of them accept them) and everybody is happy: she gets to sit on them, her husband gets to feed her in the nest and I don't get babies.