If you're trying to breed parakeets, the way you handle the eggs is critically important. Female parakeets lay eggs whether or not they've mated -- if you know the eggs aren't fertile, you can safely remove them. If your male and female pair breed, but you don't want little parakeets, you can remove the eggs. But if you want the eggs to hatch into little budgies, that's another story.
Budgies reach sexual maturity between the ages of 3 months and 4 months, but it's best to wait until birds are fully mature -- about 1 year old -- before breeding. In North America, parakeets breed between October and March. For best results, ensure the mating birds are both healthy and genetically sound. Separate the breeding pair from other budgies or birds. While wild parakeets breed and raise young in colonies, eggs and chicks are at greater risk in a multiple-bird domestic environment. Provide your breeding pair with a large nest box lined with pine shavings.
Female budgies generally lay between four and eight eggs per clutch, laying an egg every other day. Generally they won't start sitting on the eggs, to incubate them, until two or three are in the nest. Once they're finished laying, female parakeets will sit on them for 18 days before they hatch -- assuming the birds mated with a male. During this time, you must keep the breeding cage as clean as possible. Stick to a regular routine so you disturb the hen as little as possible. Don't touch the eggs unless absolutely necessary. If you must handle them, wash your hands first with antibacterial soap. Bacteria on your hands could absorb into the shells to the detriment of the incubating chicks.
Parakeet chicks hatch not at once but in the order in which they were laid -- so the first-born chick can be quite a bit larger than the youngest, at first. Budgie chicks are born naked but develop pin feathers rapidly. For the first three weeks, the father retrieves food for the mother, who feeds the chicks. Between the ages of 4 weeks and 6 weeks, at which point they are weaned, the father will also feed them. You can touch budgie chicks before that, though -- as soon as the chicks reach the age of 2 weeks, you can start handling them a few minutes each day to tame them. Always wash your hands with antibacterial soap prior to handling.
Leaving the Nest
When the babies reach the age of 6 weeks, remove the new fledglings from the parental cage -- otherwise ,the father budgie may become hostile to them. He's ready to breed again and resents the presence of the adolescent birds. Of course, if you don't want any new babies, remove the mother and father parakeet and put them in a cage without nest boxes. If the female lays eggs, remove them as soon as you find them. While you could separate a breeding pair to ensure they don't produce fertile eggs, if they're truly bonded, separation can prove emotionally disruptive to the birds.