[Preliminary examinations on the effects of the breed characteristic feature "feather crest" on skull and brain anatomy of domestic ducks (Anas platyrhynchos f. dom.)].

As mentioned in older sources, the crested breed of the domestic duck is described as variety with high pre- and postnatal mortalities, malformations in skull and brain anatomy, and several central nervous deficiencies in affected birds. Therefore this breed is to be called defective and abnormal in the sense of section 11b of the German protection of animals legislation. Poultry fanciers reject these findings as incorrect, but accurate scientific examinations that bear out this allegation are not available. Preliminary examinations have demonstrated that brain and skull anatomy of living animals can be described by using non-invasive diagnostic techniques (magnet-resonance-imaging, computerized tomography, radiography). The use of this progressive methods enables to expressive findings on present stocks of domestic ducks. Many of the test animals investigated in preliminary examinations by using magnet-resonance-imaging and radiography showed abnormal tissue deposits in the tentorium cerebelli, meningo-encephalocele, cranial malformations, and variable bone formations in the thickened hypodermis of the crest. If crested ducks are mated against each other, numerous offspring show malformations of upper beak and cranium, encephalocele, as well as craniopagal parasites in form of rudimentary legs.