Crested chickens

A skull excavated in England suggests that crested chickens were present there in Roman times.

[1][2] Early depictions of these birds are found in the Ornithologiae tomus alter of Ulisse Aldrovandi of 1600, and in the work of Dutch animalier painters such as Melchior d'Hondecoeter in the later seventeenth century.

Apart from these breeds, crested chicken are found in Africa and Iceland.

This means, that homozygous but also heterozygous animals show a crest, which is however more pronounced in homozygotes.

Neurobiological investigations showed that this malformation alters the brain anatomy without any functional relevance.