Any cockateil breeder out there

[mychocolabs]

I have a pair of cockateils that have laid their first clutch of eggs.  The first egg is 30 days old today.  No eggs have hatched yet, and I am not exactly sure of when they started incubating the eggs.  Yesturday they decided to mate again and today they pushed one of the eggs out of the nest, is this normal, do I just continue to leave them alone.  Do they normal begin to mate again before the first clutch has even started to hatch and why would they push an egg out of the nest, especially if they have been incubating it for so long (the 6th egg will be 21 days old on 4/22)  Thank in advance for the help.

[GoatTalker]

http://www.ntu.ac.uk/ares/facilities/animal_unit/animals/index.html#

I would throw out the old egg, and candle the rest, I'm betting they are not fertile. To candle, you hold the egg over a bright light-flash light, pen light, light bulb. You want to see veins or a large dark circle with egg veins.