I don't know any thing about Hereford genetics but I can tell you that they have a humble background,no fancy breeding program as such.They simply cropped up in a feeder breeder colony by chance,that breeder shared some photos with a mouse club member.That member liked them,took a few on and set about establishing them as a new variety.All the ones I have handled have been of decent size,not at all like the dutch.Over here red,black and chocolate are the most common colours.