Is it okay to let them choose their mates no matter their color? I saw video that breeding a red head with a black head could mean the female chicks would die and the male chicks only have a 50% chance (or some such similar warning). But someone else on internet said crossing green back with blue back STRENGTHENED the genetics.
Can someone tell me where I might find information on what the colors mean? You all talk about 'looks like dilute' or 'silver' or various phrases and I am clueless to what you all mean. Can you recommend books or links to explain this? Gouldians are confusing - it is almost like breeding different creatures together! If various color combinations aren't a good idea, I'd like to keep them from breeding and hurting the genetics of this species. Thank you. Oh and I love reading and I'm not afraid of heavy reading.

UPDATED: I ask you'all about books because I know ANYONE can write a book. I want to read books to learn FACTS and not some hon-yawk's opinion on the subject. You, who actually breed them, are the experts - that's why I ask here for trustworthy authors or information.