Colibacillosis in Poultry

Small and Backyard Flocks May 05, 2015 Print Friendly and PDF

Written by: Dr. Jacquie Jacob, University of Kentucky

Colibacillosis, also called  mushy chick disease and cellulitis, is infection by the Escherichia coli (E. Coli) bacteria. This disease affects all poultry as well as wild birds. E. coli is the most common bacterial pathogen in poultry. It is spread through fecal contamination of eggs, feed, and water. It is often the cause of secondary infection when the immune systems of birds in a flock are compromised due to another disease, especially mycoplasma.

Clinical Signs

Clinical signs of colibacillosis include the following:

  • Low performance in older birds (due to tumors)
  • High mortality in younger birds (due to yolk-sac infections)
  • High embryonic mortality in breeder flocks
  • Respiratory distress
  • Diarrhea


Antibiotics can be used to treat infection.

Prevention and Control

A vaccine is available for breeders and layers. To prevent infection on your farm or ranch, purchase only mycoplasma-free stock from hatcheries registered with the National Poultry Improvement Plan (NPIP) registered hatcheries.

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This work is supported by the USDA National Institute of Food and Agriculture, New Technologies for Ag Extension project.