School Textbook wrong on Chicken Genetics?

[Wyandottes13]

Attention all geneticists, help needed!
In my Biology textbook for school is this paragraph: (sorry for blurriness)

The SOP, under the definition of barring, says that barring is determined by a sex linked factor for Plymouth Barred Rocks, Dominiques, "Cuckoo group" , but for Hamburgs and Campines barring is determined by a recessive non-sex-linked factor. This raised to mind the question, "Isn't barring then determined by two different genes, in addition to color genes?" If true then the paragraph is misleading, if not false. It would be that the two genes for barring determine barring, not the genes for the phenotype of black and white colored chickens. Also, has anyone ever bred a white and black chicken and not gotten a barred chicken? What were the results? Did the chicken simply lack the barring genes?
Also, a bigger problem arises in the Punnett square illustration. 1) both parent chickens appear to have white legs. Since white is a dominant trait for shank color, then why does all offspring have yellow colored shanks, which is a recessive gene? If the parents were both heterozygus for white and yellow shanks, then one (25%) of the offspring would have yellow shanks. 2) The mother has a single comb and the father has a rose or pea comb. I thought single combs were recessive, so all offspring should have rose or pea combs. 3) Their are chickens are all separate breeds. The black chicken is an Australorp, the white chicken is simply listed as "white chicken" so it is probably a production mutt, and the offspring seems to be a cross also, having the unorganized barring of Dominique, but a single comb though. 4) The MOTHER and FATHER are both HENS, and the offspring are all males. Yes, I know they only used one picture for the offspring, and there is a 50/50 chance between male and female offspring. But seriously? These people didn't even have the brains to search "black rooster" instead of black chicken. The photographer even lists the picture as "Black Australorp Hen Isolated." As if they didn't know, or didn't care that a hen is female.
The reason why I'm posting is that I want to get my facts straight, because I really have the mind to email the company whom makes this textbook. Please feel free to discuss .

 

[sylviethecochin]

It's worse than that--for both cuckoo and barring, the white isn't actually white--it's an absence of pigment that has absolutely nothing to do with white. (that, sadly, is why we cannot not have black and gold striped chickens, except for gold quill (the color of gold campines))

A white and black cross would have one of three outcomes--1.) recessive white would be almost completely concealed by black. 2.) dominant white would almost completely conceal black, 3.) an unknown allele hidden by the parents expresses. Say if the white rooster had a concealed barring gene (it's hard to show barring when you're white anyway) and he was recessive white. Then all of the offspring would be barred black. That would only work if the rooster was homozygous barred, because your SOP is right--it is a sex-linked trait.

A far better example would be the crossing of a splash (true blue) hen and a black rooster. All of the offspring would be what we call blue, because splash and black are co-dominant.

Try this calculator--it's fun.

Since the chart is only being used to illustrate color, it seems unfair to penalise it for the legs and combs, though--especially as laying hens often start out with yellow legs, only to lose the pigment when they begin laying. It's actually somewhat reasonable for rooster offspring to retain the yellow legs.

 

[RiverOtter]

I'd be more concerned that both parents are hens.

But seriously, it is a textbook page on basic genetics, I'd not worry too much about the picture.
Of course it isn't going to go into all of the huge variables that form chicken genetics, it is a basic introduction to the fact that genetics isn't like mixing paint and there are more factors at work than phenotype, and if it succeeds in teaching even that much to students, it's good.