One thing many people don't realise is that when they buy seed from the supermarket or other budget stores it most likely imported seed that has been heat-treated to kill any bugs or other nasties. But, unfortunately, the heat treatment also kills most of the goodness in the seed.
If you want to see how good your seed is - sprout some. Heat-treated seed won't sprout many seeds at all, but locally grown seed will have a much higher success rate. In fact, your bird will probably love having some sprouted seed included in their diet on occasion.
In New Zealand the biggest provider of locally grown seed is probably Topflite and should be available from your local pet store, Farmlands, or from online stores such as Trade Me.
But, don't forget that your birds need plenty of fresh fruit and vegetables as well.