Artificial Incubation of Exotic or "Non-domestic " Bird Eggs


Artificial incubation of bird eggs is
not a new avicultural practice,
although the actual origins have been
lost in the passage of time. One of the
first records of human beings artificially
incubating and hatching eggs
was written in the fourth century
B.C. by Aristotle. In his writings about
animals, he described some of the earliest
known techniques: "in some
cases, as in Egypt, they are hatched
spontaneously in the ground,by being
buried in dung heaps. Instances have
occurred of eggs being deposited in
warm vessels and getting hatched 

spontaneously" (Aristotle, 1910). De
Reaumur (1750) also wrote about the
success of the sun-dried mud brick
(adobe) incubating ovens of ancient
Egypt, and is quoted as saying "Egypt
ought to be prouder of them than her
pyramids." Techniques involving
chicken and duck eggs also originated
during the same time period in ancient
China and spread to what are now the
Philippine Islands, Vietnam, Laos,
Cambodia and Taiwan.
During the 20th century, the poultry
industry elevated the art of artificially
producing chickens into the realm of
modern science, and today it is an
international food industry. Techniques
for producing, storing, incubating
and hatching eggs are
well researched and continually
improving. Unfortunately, the correct
husbandry techniques for artificially
hatching most exotic or "nondomestic"
bird eggs are still in the
experimental phase. However, the
basic principles which govern the
development of the chicken in an artificial
environment also applies to
other bird species. Poultry literature is
an excellent source for learning techniques
and determining causes of
mortality in exotic birds.
Today the role of the aviculturist is
expanding, and effective captive
propagation programs incorporate
knowledge from disciplines such as
avian science, field biology, genetics,
nutrition, veterinary science and
behavior. The exotic bird industry
which involves zoos, conservationists
and private aviculturists is evolving
very rapidly. Age-old avicultural wisdom
combined with poultry techniques,
such as artificial incubation and
information about birds in the wild,
improves husbandry and maximizes
reproduction in a captive environment.
The benefits of artificially incubating
bird eggs are well known. Captive
birds do not always incubate or hatch
their eggs successfully and inadequate
parental care often results in egg
abandonment, breakage and chick
mortality. Manipulating egg production
by removing eggs from the nest
for artificial incubation and hatching
also induces hens to "double clutch"
and lay additional eggs during the

breeding season. This is a management
tool which has been used successfully
when the production of additional
chicks is critical, as in the case
of endangered species such as the
Whooping Crane (Crus americana),
San Clemente Loggerhead Shrike
(Lanius ludovicianus mearnsi)
(Kuehler et al., 1992) and the California
Condor (Gymnogyps californianus)
(Erickson and Derrickson,
1981; Kuehler and Witman, 1988).
The successful hatching of eggs in
an incubator requires two things: a
"potentially hatchable" egg and an
adequate incubation environment.
First, in order for an egg to be potentially
hatchable it should be clean and
free of viral, bacterial and fungal infection,
and it must have been produced
by genetically and nutritionally sound
parental stock. Contamination,
inbreeding and inadequate maternal
diet can result in eggs which are not
hatchable under conditions of either
natural or artificial incubation. The
second requirement is the correct
incubation environment. This means
that the dry bulb temperature, humidity
level and turning process is appropriate
for optimal embryonic development.
Egg Storage
To improve the chances for a successful
hatch, eggs should be set as
soon as possible. Egg storage is a husbandry
technique which enables
breeders to hatch clutches together
and simplify the chick rearing process
by producing birds which can be
brooded in like-age groups. However,
proper techniques for egg storage are
often overlooked which results in an
increase in early embryonic mortality,
poor hatchability, prolonged incubation
periods and weaker chicks (Proudfoot,
1968; Chahil and Johnson,
Loss of hatching viability appears to
be species dependent and very little is
known about the storage tolerance of
non-domestic bird eggs. For example,
Chukar (Alectorus graeca chukar)
eggs can be stored for as long as 28
days without any effect on hatchability,
while Cockatiel (Nymphicus hollandicus)
clutches stored for only six
or seven days show a reduced hatch

rate; eggs stored for longer than eight
days do not hatch at all (Woodard and
Morzenti, 1975; Roudybush, 1984).
If storage is necessary, nondomestic
eggs should be maintained
at 12.8 to 18.3°C (55 to 65°F), at a relative
humidity of 80 to 90 percent,
for no more than seven days
(Schwartz, 1977; Roudybush, 1984;
Kuehler, pers. obs.). Holding temperatures
above 26. 7°C (80°F) will allow
cell division to continue at an abnormal
rate resulting in decreased hatchability
and abnormalities in the brain
and eye regions of developing
embryos. There is also some evidence
suggesting that placing eggs in finepored
plastic bags that allows some
air circulation, increases the hatchability
of stored eggs. The incubation period
is still longer than normal because
some embryos, from stored eggs,
require a longer developmental period
(Bowman, 1966; Schwartz, 1977).
Sanitation/Egg Contamination
Parent birds and the hatchery itself
are both recognized as potential
sources of infection in newly-hatched
chicks and incubating eggs. Because
the hen uses a common passage for
both eggs and fecal matter, and the
incubator environment is warm and
moist, embryonic diseases are caused
both by the intestinal contents of parent
birds and contamination from
incubators and hatchers. Microbial
contamination resulting in infection is
of two types: exterior eggshell-borne
diseases and interior egg-borne diseases.
Contaminants are more easily
eradicated from the surface of the
shell than from within the egg.
Hatchery sanitation should include
maintenance of disease-free birds and
a well ventilated, easily cleaned incubation
and hatching area. Protocols
which emphasize egg handling with
clean, dry hands and a flow pattern
which minimizes traffic from areas
that are possible sources of contamination
(such as adult breeding stock)
are optimum.



Editor's Note: Because Keuhler's

literary references were 96 in number

and her incubation parameter charts

occupied 11 pages, it is not practical

to publish them here. They are available

by requesting them from the AFA

Home Office. •