red rumped parrots?

[spish]

im looking for a little info on breeding these......i have a couple that are about 2 years old yet the lady has never laid eggs? do they breed later in life or is it time to change ladies? perhaps i need more ladies (like a trio?) they live in an indoor aviary, first they had budgies in with them but i took these out to give them some privacy. ive gave them a huge breeding box and also a hollowed out tree stump to nest in, there is peat and woodshavings available as nesting materials if they wish to choose something but they've never been touched. they have plenty of flying room. cant think what else im missing?