Hi,
Birds will breed with or without a nest box, but they are more likely to breed if they have one. And even if they do breed and lay eggs, you do not have to provide a way for them to hatch the eggs. If the cage floor has a metal grate, that will prevent them from being incubated. If there isn’t a floor grate, then you can either try discarding the eggs, and if she still lays eggs, replace them with fake eggs that can be ordered online. An egg doesn’t begin to grow until it has been incubated around the clock for at least 48 hours.
You can discourage breeding entirely by doing certain things. Most birds are triggered to breed when the days are longer, weather is warmer, food is abundant and they have a safe place to nest. Never give them anything they can get inside of – no boxes, bird tents, huts, large food bowls. If you ever notice the female starts to sit in one bowl all of the time, replace it with smaller food bowls. If she picks a corner of the cage. put toys there to discourage her. Never give them paper or cardboard to shred. If they don’t have a metal floor grate, never use any shavings or anything soft for the cage bottom. Always keep the cage clean. Rearrange toys every once in a while. In spring, limit their light to no more than 8-10 hours daily by covering the cage early each evening. And keep the cage in a busy place in the house – too much privacy and quiet can trigger breeding.
Thank you for asking Lafeber,
Brenda