Direct from a trusted breeder "As of yet, though, there are many nice samples of 'blue' birds, this has all been about selection of the bluest birds possible, which they seem to have really excelled at in Europe. But, these birds may still turn color and I think many do, at three years old and older, where they get a pinkish head and some green on the back. Plus, when bred, they can still throw babies that have the psittacine and have the greenish marks in the blue, like most turquoise that are seen. Here is an article by Dirk van den Abeele, who is from Belgium and has been studying lovebird feathers for a long time, though, he is really only an amateur scientist. Actually, I think you have to look at his website, yourself to see the article. Once you're on the website, click english, than on the left hand side, click Articles, under the article section there is one under Agapornis Roseicollis, called The Evolution in turquoise roseicollis and it will give you a whole lot of info about your question."
I believe the same goes for the GCC. There have been birds that have been bred to look more and more blue. But they are all still crosses of the turquoise mutation.
