Classical, medieval, and modern parallels
I do not know of any classical prototypes. The Roman
hen and goose houses described by Columella and Varro
were buildings of rectangular shape.[601]
But the question
arises whether there may be some typological connection
between the hen and goose houses of the Plan of St. Gall
and the circular bird house which Varro built in his villa
at Casinum.[602]
There appear to be no medieval parallels,
unless a circular enclosure with two rectangular attachments
on the grounds of the tenth-century royal palace at Cheddar,
in Somerset, England (fig. 470)—which its excavator,
Philip Rahtz, interpreted as a mill with grain bin and
bakery—was in reality a chicken house. The light construction
of its walls, all braided in wattlework, may speak in
favor of such an assumption.[603]
In his model of 1877 Julius Lehmann reconstructed the
poultry houses of St. Gall in the image of a medieval dovecot
(fig. 267). He interpreted the outer circle as a wall, and
the area between this circle and the inner circle as an open
poultry run. Besides the fact that this interpretation completely
disregards the existence of an intermediate circle,
Lehmann's solution involves a conspicuous imbalance between
running and roosting space and would appear to
be incompatible with the functional perspicacity that the
author of the Plan exhibits in the handling of all other
details of this nature.
The clue to the riddle may be found in an octagonal
chicken house built in the nineteenth century by Freiherr
von Ulm-Erbach, and described in 1886 in Bruno Dürigen's
monumental work on poultry breeding (fig. 472).[604]
Dürigen referred to the design of this house as "a formerly
favored" but "now superannuated" form that had a long
tradition and was used in many zoological gardens because
of its specific suitability for exhibition purposes.[605]
The
house is 26 feet (8 meters) in diameter and 23 feet (7
meters) high. Like the poultry houses of the Plan, it has
three concentric strips of space and only one entrance. The
outermost strip is open to the sky and serves as a daytime
run for the chickens. The intermediate strip is roofed
over and serves as coop, leaving in the center a tower-like
projection, the raised roof of which admits air and light
through clerestory windows. The chickens are fed and
watered from this center space, and the house can be
heated by a stove set up in this area.
The portion serving as coop consists of a lower and an
upper tier, the lower being used for laying and brooding,
and the upper, for fattening.[606]
Both tiers have trap doors
toward the chicken run which can be closed at night, with
ladders enabling the birds to descend to the ground from
their roosting pens and to ascend again in the evening.
Freiherr Ulm-Erbach's chicken coop had a housing capacity,
on the lower tier alone, of 192 birds. The Hen House
of the Plan, which is practically identical in dimensions,
could have accommodated the same number—and if it
were meant to be a double-tier arrangement, twice that
number. For the geese and ducks (should anseres be a
generic term for both of these breeds) this figure would
have to be reduced by a ratio commensurate with their
larger size.
In Roman times, according to Columella,[607]
one laborer
was considered sufficient to care for 200 chickens. On the
Plan of St. Gall the keepers of the hen and goose houses
are referred to in the singular, but the rooms in which they
sleep are large enough to accommodate beds for three or
four additional hands. The raising of chickens is a year-round
operation; but geese generally mate in December,
so that goslings can be grazed in the open fields in the
spring, without supplementary feed and extra housing
(fig. 467). The guarding of these flocks would require
additional hands.