Sexing lovebirds isn't easy, even for experienced breeders. You might not realize you have a female lovebird until you find an egg in the cage. If you do know your lovebird is female, watch her behavior carefully for signs of incipient egg production. You won't see much in the way of physical signs that she's about to lay unless she's experiencing a problem.
Bonded or Not
If you have a female lovebird, she'll lay eggs whether or not she shares her cage with a male. Of course, a single female's eggs won't be fertilized. If you do house a male and female lovebird together, be aware that they reach sexual maturity between the ages of 6 months and 1 year. While a single female lovebird will likely focus her primary attention on her caregiver, once she has a mate, the pair generally becomes bonded. There's a reason two people deeply in love are described as lovebirds. Like their namesakes, they only have eyes for each other.
Discouraging Egg Production
Lovebirds tend to lay a lot of eggs. To discourage egg-laying, keep your female lovebird separated from other birds, in a cage of her own. Make sure she goes to bed early. Short days discourage laying, as they mimic winter hours when the lovebird doesn't breed. It's not enough just to cover the cage -- move it to a dark room where people won't be watching TV or working on their computers. If she does lay an egg, leave it in the cage, especially if you know it's not fertilized. She can happily sit on it for three weeks, and her body might turn off the hormones to produce additional eggs.
You can tell that your lovebird might start laying eggs when she starts displaying nesting behavior. In the wild, she'll spend her time gathering leaves and chewing them into strips to create her nest. Caged female lovebirds make do with whatever materials they have, which could include their seed cups. If you see your lovebird exhibiting nesting behavior, you'll realize two things. The first is that your pet is female, while the second is that she's preparing a place for egg laying.
Lovebirds are among the types of pet birds prone to egg-laying difficulties, some of which can prove fatal. Egg-binding ranks among the most common issues. This occurs when the lovebird can't expel an egg. Symptoms include straining, depression, appetite loss and even paralysis. You might see a large bulge in the ventral area, which is the egg unable to pass. Egg-binding constitutes a veterinary emergency. Your vet might give your bird fluids or inject medication into her to relax her muscles and allow the egg to pass. If that doesn't work, your vet might aspirate the egg contents with a needle, causing the shell to collapse as it empties. The broken shell usually passes on its own; if it doesn't, surgery might be required to save your lovebird.