What "split" means in conure genetics
"Split" is the most common word in a green-cheek sales advert and the one most often used wrongly. It is not a colour, not a shade, and not something anybody can see. It means the bird carries a gene it does not show — and every breeding plan you will ever make rests on knowing which of your birds carry what. If you would rather skip the theory, the colour calculator takes two birds and works it out for you.
Predictions are statistical. Percentages describe a theoretical infinite clutch, not the four eggs in front of you, and mutation names vary between breeders and countries. Why this matters more than it sounds.
A recessive gene needs two copies before it shows
Most green-cheek colour mutations are recessive. The bird has to inherit the same gene from both parents before it changes how it looks. One copy on its own does nothing visible at all — it sits there, fully functional, and gets passed on to about half the chicks regardless.
A bird with one copy is split to that colour. Breeders write it with a slash: a green bird carrying one turquoise gene is normal/turquoise, said out loud as "normal split turquoise". The part before the slash is what you see. The part after it is what the bird is hiding.
You cannot see a split. Nobody can.
This is the part that matters in practice. A normal/turquoise conure and a normal conure with no turquoise anywhere in its family are identical — to your eye, to a photograph, to a judge, and to an avian vet. There is no subtle tint, no shading on the flights, no tell. The two birds look the same because they are the same everywhere the gene is not doing anything.
So there are exactly two honest ways to know a bird is split:
- Its parentage. If one parent was visually turquoise, then every single chick carries at least one turquoise gene. That is not an estimate — it is the only thing that parent had to give.
- A test pairing. Put the bird with a visual of the colour in question. If any chick comes out visual, the bird was split. If none do over several clutches, it probably was not, though "probably" is the strongest word available.
Which means "split to turquoise" in an advert is worth exactly as much as the pedigree behind it. Ask which parent it came from. A breeder who has actually tracked it answers immediately and without irritation.
A hen cannot be split to cinnamon or yellow-sided
Not every gene behaves the same way, and this exception is worth committing to memory because it is the one that gets sold to beginners.
Turquoise and dilute sit on ordinary chromosomes, which come in matched pairs in both sexes. Either sex can therefore carry one hidden copy.
Cinnamon and yellow-sided do not. They sit on the sex chromosome, and in birds it is the hen who has only one of those. There is no second copy for anything to hide behind. She either carries the gene and shows it, or she does not carry it.
So a "cinnamon split hen", or a "hen split to yellow-sided", describes a bird that cannot exist. If you read it in a listing, the seller is repeating something they were told. Cocks have two sex chromosomes and can absolutely be split to both — in fact most of the interesting pairings in this hobby involve exactly that. There is a separate article on why the father decides his daughters' colour, which is the same fact viewed from the other end.
What it means when you plan a pairing
For an ordinary recessive like turquoise, over a large enough number of chicks:
- split × split — about one chick in four is visual, and half the rest are split. You cannot tell those two groups apart without testing.
- split × visual — about half are visual, and every one of the others is split.
- visual × visual — all visual.
- normal × visual — none visual, every chick split.
Those are proportions over a theoretical infinite clutch. A real clutch of four or five can miss them entirely and nothing has gone wrong; four heads in a row is not evidence of a two-headed coin.
The short version
- Split means carries but does not show.
- It is invisible. Only pedigree or a test pairing proves it.
- Turquoise and dilute: either sex can be split.
- Cinnamon and yellow-sided: only cocks can be split. A split hen does not exist.
- Two splits together can produce a visual chick. One split on its own never can.
Work out a specific pairing
The calculator takes two birds described the way you actually see them — a colour and a sex, plus "don't know" for anything untested — and gives you the chicks with the certain results separated from the ones that depend on a split you have not confirmed.