Blue partridge. When you try to get blue partridge hatching eggs, you will get a mix of gold partridge or splash mixed with the blue. The reason is because of the way the black inhibitor (blue) gene works. With one copy in your bird, you get blue. With two copies, you get splash. With no copies, you get gold. So, if you breed two blues together, 50% of the chicks will be splash (or there abouts). If you breed a gold and a blue, 50% of the chicks will be gold. So, that is probably more information than you wanted, but there it is.