Disease status of US flocks –
no major problems
Non-con;ned ;ocks exhibit conditions observed before con;nement
housing was adopted by the industry. Eric Gingerich, DVM, ACPV
In preparation for a presentation to the 113th Annual Meeting of the United States Animal Health Association,
a questionnaire was sent to members
of the Association of Veterinarians in
Eric Gingerich
Egg Production
to document the
disease status
of U.S. ;ocks.
The respondents were all involved in health
maintenance as
diagnosticians
in state and federal laboratories, consultants,
company veterinarians and professionals af;liated with primary breeders
and the pharmaceutical and biologics
industries.
‘Starveouts’ reported for
caged flocks
Generally the survey did not disclose any major problems relating to
the health of either
pullets or laying
The survey results for caged pullets
con;rmed problems relating to chick
quality and the effect of stressful environments on viability. “Starveouts”
and yolk infections were the most important conditions reported. Peripheral
neuropathy, an autoimmune condition
affecting the nervous system, clinically
resembling Marek’s disease, appears
at 5 to 8 weeks of age in replacement
;ocks, mostly of two strains. Coccidiosis and ILT were seen occasionally
but were not regarded as
signi;cant problems in
pullets.
;ocks. This situation is attributed to
a number of factors,
including:
✔Elimination of
vertically transmitted
diseases by primary
breeders,
Factors that contribute
to cannibalism:
✔Lack of socialization in
pullet phase
✔Failure to provide perches
and “escape areas”
✔Improper beak treatment
✔High light intensity
✔Diligent vaccination with live and inactivated agents,
✔An increased awareness of the importance of biosecurity, cleaning and
disinfection, and
✔Implementing good production
practices especially with regard to ventilation.
For caged layers, E.
coli peritonitis was the
most serious condition followed by cannibalism and myco-plasmosis. “Calcium
depletion” which is
effectively osteomalacia is observed
in underweight pullets subjected to early light stimulation when approaching and after peak
production. Coccidiosis and focal duodenal necrosis are observed in some
;ocks on a regional basis.
The survey was divided into ;ve sections dealing respectively with caged
pullets, caged layers, non-con;ned pullets, non-con;ned layers and emerging
issues of concern.
Respondents rated the importance of
diseases on a scale of 1 to 4 depending
on severity and incidence.
or under free-range management demonstrate the diseases and parasitic conditions observed over ;fty years ago
before con;nement housing was universally adopted by the industry.
Non-con;ned pullets show coccidiosis in addition to the losses during the
;rst week associated with “starveouts”
and yolk infection. Rearing on litter
leads to ascarid verminosis. It is noted
that capillariasis, which is frequently
encountered in backyard ;ocks was
not cited as a condition diagnosed in
commercial ;ocks. It is possible that
these parasites affecting either the crop
or the intestine are missed on ;eld examination as they are dif;cult to visualize and may in fact occur in free-range hens.
Among non-con;ned producing
;ocks, cannibalism and colibacillosis
were the most signi;cant causes of
mortality. Mites and ascarid worms
were ranked second and coccidiosis
the third most frequently encountered
infection.
Fifty-year-old conditions seen
Non-con;ned ;ocks in either barns
Organic flocks treatments
needed
In reviewing conditions other than
disease affecting the industry, welfare issues were considered to be the
most important. Absence of approved
effective treatments, especially for organic ;ocks was noted as a signi;cant
restraint to therapy and averting mortality. The need for a broader range of
more effective vaccines was stressed.
Salmonella enteritidis and avian in-;uenza were ranked highly among the
concerns confronting veterinarians in
egg-production.
Many of the respondents noted an
