oh, that's what it says. Thanks!I think what it says is: some scientists got a bunch of 1day old chicks from a bunch of Egyptian breeds plus some non-Egyptian breeds. They were not vaccinated for Marek’s and no antibodies for Marek’s from their moms. A number of the Egyptian breeds have this gene - Chb6 - that is implicated in resistance to Marek’s disease, but not all of them and not the non-Egyptian breeds. The scientists infected the chicks with Marek’s, and then tested their spleens for the presence of Marek’s at various week intervals. They found that the Egyptian breeds with the Chb6 gene didn’t have the Marek’s disease tumors even though they were infected with it.