Yeah that is bizarre. I liked the sources of it though and I think their logic is correct. I assume that was an accident! Perhaps it might be best then just to look at their sources to further research the trend but I am on your page that rose combs are linked infertility and that the wording is wrong.And whoever wrote that conclusion has a typo:
"the gene for heterozygous rose comb is linked with poor reproductive ability."
"Heterozygous" does not belong in that sentence, since the homozygotes are the ones with problems (as shown in the rest of that paragraph, and the studies recounted in the body of that paper.)
@Rhodebar Lover I see that you copied it exactly from the paper, so my criticism refers to the actual author of the paper. They really needed to proofread that!