T. Bartels et al., Osteological investigations of the incidence of cranial alterations in domestic ducks (Anas platyrhynchos f. dom.) with feather crests, ANN ANATOMY, 183(1), 2001, pp. 73-80
The feather crest of the domestic duck (Anas platyrhynchos f. dom.) represe
nts a peculiar mutation of the integument of the head, which has been known
since the 17th century. In literature this is described as a variety with
malformations in skull and brain anatomy in which various central nervous d
eficiencies in affected birds are possible. Our examinations demonstrated s
everal conspicuous anatomical alterations in the skulls of domestic ducks w
ith feather crests. Osteophytes of different size in the hypodermis of the
crest integument were found as well as cranial perforations located in the
parieto-occipital region. In morphometric studies, a significant increase i
n the capacity of the cranium was found in Crested ducks compared to other
examined breeds (Abacot Ranger, German Pekin ducks). This increase in crani
al capacity in Crested ducks results from the occurrence and enlargement of
a tentorial fatty depot during craniogenesis. The formation and enlargemen
t of the fat body can influence cranium growth as long as the cranial bones
are not entirely fused. Thus, in comparison to other phenotypically simila
r domesticated birds like the crested chicken, the expression of feather cr
ests in domestic ducks demonstrates symptomatologic differences. In conclus
ion, our examinations demonstrate that the skulls of Crested ducks show var
ious peculiar morphological alterations whose genesis is up to now not know
n with satisfactory accuracy. Further investigations are continuing to asse
rtain whether there are linkages between cranial alterations (malformations
of the calvaria, osteophytes, increased capacity of the cranium) and the e
xtremely high prenatal and postnatal mortalities and numerous abnormalities
described in crested breeds of the domestic duck.