Has anyone any idea why my lutino yellow girl (Marglo) would have laid an egg two days ago, then mated with my violet spangled boy (Squeak) today? I'm guessing the first egg is infertile so this may be her second chance?

How else do you thinkt he other eggs will be fertilised? Budgies mate all the time, recreationally and for breeding. Budgies who are courting and mating for reproductive purposes mate many times. This usually stops once all eggs have been laid and the hen is brooding, but will start again once the chicks have hatched and the youngest is about 2-3 weeks old in preparation for another round of eggs. Plus, the males tend to get frisky after a while anyway

To my knowledge they were not a pair, she was always cranky and wouldn't let anyone go near her. Only since she laid the egg the other day has she been with squeak and my cobalt spangle Cornelius has been feeding her. I thought she was a loner. I'll just wait and see what happens next. Thanks for your help