Often questioned about genetics, the term is split. Splitting in birds simply means a genetic trait and / or color that is worn but not visually visible.
Sometimes there may be feathers in the neck (white spots perhaps) that reveal that a bird can clearly have some other color mutation or trait than what it visually appears to be. Or it could be something like a white toenail on a particular type of bird that would normally be black.
I like to think of these as little secrets and clues to what may be a new color or property, other than what can actually be seen.
My favorite is the unexpected. When a bird looks ordinary and produces the unexpected (shared and you can not say).
# 1 Example: Gray cockatiel male X gray cockatiel hen = 100% all gray chickens. But if I get a lutino kid in the nest, what does that mean? How could this have happened? Well, lutino is a sex-linked gene in itself, so it means that gray male (dad) is a shared lutino, and we can pronounce this lutino (girl) to a girl. Because the hen (mother) is gray.
Father to daughter, mother hen must be a visual lutino and father split or visual to produce a lutino male chicken. Half of all gray male chickens will also be split lutino, and not all chickens (girls) will be lutino some will be gray but not split!
# 2 Example: Use another gray pair again, if I get a chicken with a white face in the nest. I know that it takes two recessive white face genes visual or non-visual (split) to make a recessive visual white face. This now means that the gray male (dad) is split in the white face! And gray cockatiel hen (mom) is also split white face! So this white bride can be a boy or a girl. Now brothers and sisters who are gray, about half of these will also be divided and half will not.
I must emphasize that this article does not include pairing splits!
After going through these charts, you will see how many genetics there are. Blue ring neck, blue budgerigar, blue quaker, Dutch blue dwarf parrot, tree puppy, red cockatiel and white face cockatiel are all recessive! Lutino ring neck, lutino budgie, lutino quaker, lutino lovebird, pearl cockatiel, cinnamon cockatiel and lutino cockatiel are all sex-linked! Albino ringneck, albino budgerigar, albino quaker, creamino lovebird and albino cockatiel are all “recessive and sex-linked”. And yes, you can have more than one recessive gene on a bird and a combination of recessive and multiple sex-linked, but we’ll save this for next time!