Hello! I’m trying to find an answer for this: why when F1 Harles get bred with F1 Harles, do the chicks (F2 Harlequins) get brown feathers, look sickly/ill, and most die around 10-13 weeks of age but it doesn’t happen to F2 Catalina’s or F2 Rubys. This has always confused me. Thanks!
F1 =...