Pink-eyed Gene and Size

In outcrossing my import tans, I've bred litters with both black-eyed and pink-eyed bubs in the same litter. Each time I have both, I've found that the pink-eyed babies are significantly larger. A lot larger. Weirdly larger. I never noticed this in my litters before, but it's thus far repeated itself in the import outcross litters. Right now in the nest, I've got a mixed black and dove litter (champagne tan mum, black tan dad carrying p), and the doves are over half again the size of the blacks. True, one of the doves is a buck, and I expected him to be somewhat larger, but his dove sister is just as big as him!

They were born with the two doves minimally but noticeably larger from birth. This was true for the previous black&dove mixed litter out of the same buck but a different doe. Is this just a fluke, that the black-eyed pups have been smaller, or is it part of why pale selfs are always the biggest, typiest varieties?