I've had no issues removing eggs from females... so long as I changed up their environment, removed their nesting spot or what they were kept in, they stopped laying eggs. Casey's laid 3 clutches of eggs, however, she's never sat on them cause I took her nesting sites away, plus the eggs. Being a very loving mother (who probably wouldn't have a clue on how to care for chicks) she didn't mind me handling her eggs at all! Actually, she only seemed curious as to what I was doing, but nothing aggressive!
I was given two chronic egg laying females. One, Tomi Girl, has never laid an egg for me. I've had her for over 2 years now. The other, Kiwi, laid 1 egg the day after she came here. Haven't had an egg from her since! I've had her for 2 years and 5 months (although in truth I don't know who laid the egg... Kiwi or her daughter, I do have my suspicions)
Therefore, I am not in the mind to believe that just because a cockatiel lays an egg you can't remove it or else you'll have a chronic egg layer. Tomi Girl was a chronic egg layer in her previous home but they never did anything to change her settings or change anything else around her. When she came here, I removed her eggs.
As far as fertility goes... well I heard of a lovebird who was an only hen for 5+ months (maybe 6 or more?), and she laid a fertile egg, that hatched. Either she was fertilized before, and the sperm remained viable, or she pulled off a parthenogenesis....
Virgin Birth Expected at Christmas -- By Komodo DragonI've heard of a similar occurrence with a human female who hadn't had intercourse for months.... but had an intimate relationship with someone through a chat website, and became pregnant.... however, I can't seem to find the story to say whether or not it's true.