History: A flock of about 4,000 birds per house of 20 houses per farm with female-male ratio of 7:1; Isa breed; Layer breeder. Note that only females are affected
Clinical Signs: At about 20 weeks, unilateral corneal opacity was observed which was topically treated. It spread to other birds within a house and to other house. At about 28 weeks, there was sharp drop in egg production and then low but persistent mortality of about 0.1% per house per day. This mortality persists till now and the birds are now 39 weeks. Although clinical manifestation of fowlpox is now evident in both males and females of the flock.
PM Lesions: Ovarian atresia and/or regression consistent in all the birds posted. No obvious lesions and only females are affected in term of clinical signs, PM lesions and mortality
Medical Intervention: Different antibiotics have been given to the birds (Colistin, Meriflox, Oxytetracycline,Gentamycin, etc). Also, IBV and fowlpox vaccinations have been repeated.
Outcome: Mortality still persists till date
A quick glance at the literature suggests high NH3 levels in the hen house. I couldn't do much deeper because the noise from Ammonia & too much crude fiber in the feed hid every thing else.
Ammonia acts as a very high pH irritant would not respond to antibiotics or vaccines. Look into the Nitrogen level of your feed and clean out one chicken house to see if the problem improves in that house. Or look back at your records and see if the problems change when you clean out a house.
There was a laboratory that helped us perform a molecular analysis to the samples taken from moribund animals and diagnosed the case to be Diptherithic or wet fowl pox with herpesvirus complication, most likely Infectious laryngotracheitis. could this be possible?
Following several diagnostic analyses and studies, we came up with the aetiological agent of the above observations. Kindly find attached in my profile, "The Emergence of a Novel IBV Pathotype in a Breeder Farm in Ibadan, Nigeria." for an answer to the above question.
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