I found an error in Angry Birds Movie. During the part when Terence was launching Chuck, and Chuck says "Launch me the same way you did for Red", if you look closely to the left, you can see one of The Blues, even though they have not hatched yet.
Exactly , the Blues are part of a species in this case the Blues that we know we're born in a single egg , a triplet birth. That bird there is the same species just because it has the same colour and shape doesn't mean it is the Blues.