Does anyone know of some common hybrids that use a welsummer rooster? What hens are usually used and what is the hybrid called?
The only common one I know of is Olive Eggers, from crossing a Welsummer with a blue-layer or green-layer.
The other crosses are not common enough to have special names of their own. Of course you can name them in the obvious fashion: Welsummer/Leghorn, Welsummer-Orpington Mix, etc.
I have a Welsummer Rooster that I plan to get welsummer hens for. In the meantime I would like to put some other hens in with him. I currently have cinnamon queens, Austrwhites, white leghorns, buff orphington, American game fowl, barred rock, Speckled Sussex, Easter eggers, Ameraucana.
Crossing to the Easter Eggers or the Ameraucana will give at least some Olive Eggers, but may also give some that lay brown eggs. It depends on how many copies of the blue egg gene the Easter Eggers and Ameraucanas have. For each hen that has two copies of the blue egg gene, all her chicks will inherit one, so all her daughters will lay olive eggs if they have a Welsummer father. For any hen that has only one copy of the blue egg gene, she gives the blue egg gene to half her chicks and the not-blue-egg gene to the other half of her chicks, so half her daughters will lay olive eggs and the other half will lay brown eggs. For any hen that lays brown or white eggs, she has no blue egg gene, so she cannot give it to any of her chicks.
Crossing a Welsummer rooster with Barred Rock hens will give color-sexable chicks: black chicks with a white or yellow dot on top of their head are males (white barring in the feathers as they grow), chicks without the dot on their head are females (no white barring in the feathers as they grow.) Males & females may show some red/gold leakage in their feathers as they grow up.
I think the Barred Rock hens are the only ones that will give color-sexable chicks. For any others that give varied colors, the color has nothing to do with whether the chick is male or female.
Crossing a Welsummer with an Austra White should give white chicks and black chicks, about equal numbers of each. The "white" ones may have some bits of black, and both colors may show some red/gold leakage in their feathers as they grow up.
Crossing a Welsummer with a Speckled Sussex will produce chicks that look similar to Welsummer chicks. They will not show the "speckles" of the Sussex (maybe a little when young, but not as they grow up.) The "speckles" are caused by the motting gene, which is recessive (so the chicks will carry that gene but not show the effects.)
Crossing a Welsummer with White Leghorns should give white chicks. They may have small amounts of black (like Austra Whites tend to have), and they may show some red/gold leakage as they grow up.
Crossing a Welsummer with a Buff Orpington will probably give gold or red chicks, that grow up to have less black than the Welsummer but more than the Buff parent; and the shade of buff/gold/red will probably be in between what the two parents have. There is chance of these chicks showing white instead of black in their feathers (depends on exactly which genes the Buff Orpington has, that aren't carried but not visible.)
Crossing a Welsummer with a Cinnamon Queen should give chicks that are colored similarly to their CInnamon Queen mothers. If the Cinnamon Queens have white in their tails, so will about half the chicks. The other half will have black in their trails. Or if the Cinnamon Queens have black in their tails, so will all the chicks.
I can't make color predictions for chicks from the Easter Eggers, the Ameraucanas, or the American Games because I don't know what color those ones are. But if the hen shows a lot of red/gold/buff in her coloring, the chicks probably will too. If the hen shows large amounts of any other color, her chicks have a good chance of doing it too (a Welsummer rooster has mostly recessive genes for coloring, so if the hen has any dominant genes, they will typically be the ones visible in the chicks.)
Comb types:
Since the Welsummer rooster has a single comb, any hen with a single comb will produce chicks with single combs. For any hen that has a pea comb (like Ameraucana and maybe Easter Egger) or a rose comb (maybe the Cinnamon Queens), there is some chance of the chick having that comb type too, although the chicks could also have single combs.