About Varrath Expertise I can answer most any question about tameing, feeding, housing, toys, etc. I cannot answer any questions about medical care or breeding.
I have many great Budgie books and internet sites on hand and will be happy to direct you to any of them if I cannot answer your question.
Experience I first took an interest in Budgies when I was 9.
I've owner too many birds to count since then.
I have done about five years worth of research (books, internet, etc) and consider myself to be fairly well educated.
Education/Credentials High-School and going into college
Question how do I know if the eggs my Parakeet lay are fertile and is there something I have to do or feed them to make their eggs fertile
Answer To find out if the eggs are fertile, gently hold them up to a pen-flashlight. If you anything inside, then they are. If not, then wait a few days and try again. If you still don't see anything, then I'd say not.
And I do not know if there is anything you can feed your birds. I'm sure there is, but as I said, I do not know much of Budgie breeding.