fertile

Roughly 11 weeks ago, my Male Conure passed away. Not long before his departure, I recall him mating with my female conure. Today, she has laid an egg. While I know laying unfertilized eggs isn't uncommon, is there a chance that these might be fertilized? I'm curious about the possibilities...

eg If an orange winged and a red lored were to mate would the offrspring all be infertile?

i just don't get it! i have 1 proven male and 1 proven female society finch. they are definitely a pair, and they have bred multiple times. both are old enough, and she has laid eggs before, one was normal sized but infertile, and the other was a third of the size it should be, and also...