Moving-average trigger for early detection of rapidly increasing mortality in caged table-egg layers

Sasidhar Malladi, J. Todd Weaver, Timothy L. Clouse, Kathe E. Bjork, Darrell W. Trampel

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Rapidly increasing and unexplained mortality in commercial poultry flocks may signal the presence of a highly transmissible and reportable disease. Activation of an infectious-disease surveillance system occurs when a key production parameter, i.e., mortality, changes. Various triggers have been proposed to alert producers when mortality exceeds normal limits for a given production system to enable early detection of such diseases. In this article we demonstrate that a simple moving-average trigger is useful for detecting any disease syndrome in caged table-egg layer flocks that manifests itself as sudden, rapidly increasing mortality. We superimposed HPAI disease mortality output data derived from a disease transmission model and from a naturally occurring HPAI outbreak onto normal mortality data from 12 healthy commercial egg-layer flocks, and compared the performance of 7-day moving-average triggers to previously proposed triggers. The moving-average trigger is more efficient, resulting in fewer false-positive alerts and an earlier time to disease detection. It can be easily calculated by using a computer spreadsheet providing only 7 days of mortality data and can be practically and inexpensively implemented by large commercial poultry integrators. A moving-average trigger can be an active component of a production-based surveillance system.

Original languageEnglish (US)
Pages (from-to)603-610
Number of pages8
JournalAvian diseases
Issue number4
StatePublished - Dec 1 2011


  • detection trigger
  • early-warning system
  • egg-layers
  • highly pathogenic avian influenza
  • surveillance


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