teils and keets

Question
I have a male and female parakeet. the male likes to chase the female, she dosent want anything to do with him.  How do i get them to breed?  

How can I tell the age and gender of my cockateils?  they are at least 2 yrs old and previous owner isnt sure what gender they are?  

Answer
as for the keets if the female doesn't want anything to do with him she is probably not in the mood to breed and you can't really force nature. You could add a nest box and some nesting material to encourage her but you will have to leave it to nature.

The teils - it depends on the mutation to know the sex DNA is the most reliable but various mutations can give hints. Generally the brighter the cheek patches means male but you can't tell anything for sure without DNA lutinos for example are identical bars on the underside of the tail usually indicate female but make sure this is after the first molt also some mutations won't have any bars. maybe if you tell me whci mutations I could help further but DNA is the only accurate way to know.