This head with a spiral horn is that of a rooster that died in the menagerie of the National Museum of Natural History in 1865. It has a so-called "bizarde" head, a term that usually designates deer with biologically malformed antlers. The interest for curiosities marked the 16th century. Since that time, malformations, especially deformed antlers, have been studied. Today, science has demonstrated that all the anomalies that affect them can be genetic, hormonal, traumatic, nutritional, parasitic, climatic or infectious.