Home   News

“Hardware Disease” in Backyard Chickens

By Mallory Pfeifer
“Hardware disease” in backyard chickens and other birds is caused by the ingestion of metal objects present in their environment. These objects range from sharp objects that ultimately penetrate the gizzard to objects that may contain zinc or lead leading to zinc or lead toxicosis or some other heavy metal toxicosis. Two case histories are presented to demonstrate this condition.
In the first case, one dead, 18-month-old female chicken, weighing 1.09 kilograms, was presented to the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) in Gonzales for necropsy. A two-day clinical history noted anorexia and ruffled feathers.
Upon necropsy examination, moderate breast muscle atrophy was present. When the coelomic cavity was opened, there was extensive black-colored, foul-smelling exudate surrounding the gizzard, adhering to the intestines and the left aspect of the body wall. A 1.5-cm protrusion was present in one wall of the ventriculus (gizzard) that appeared to be the original source of the exudate. Within the gizzard was a 4-cm long metal screw embedded in the protruding area (Figure 1). The screw that was removed is depicted in Figure 2.No lesions were noted in any other tissue or organ system.
Following necropsy examination, a diagnosis of severe peritonitis secondary to ventricular perforation (metal screw) was established.
In the second case, one dead, adult female black-feathered chicken, weighing 1.42 kg, was presented for necropsy with a clinical history of the owner losing a bird a day. The owner had recently completed construction of a new coop for the birds.
Necropsy examination revealed extensive feather loss over the back which appeared predominantlyto be post-mortem as the skin appeared normal and bloodless.Ahole was present in the right lateral wall of the coelomic cavity with hemorrhagic edgesand asmall blood clot along the internal surface of the hole. The intestinal tract from the mid jejunum to the colorectum wasabsent, presumed to be cannibalized through the hole in the coelomic cavity wall.
A large shelled egg was present in the distal oviduct. The ovary was normal in appearance with four developing follicles.
A few very pale foci were present in the liver. Numerous metal foreign bodies (some presumed to be zinc-coated) were present in the lumen of the gizzard (Figure 3). The crop was full of cracked seeds. No lesions were noted in any other tissue or organ system.
Following examination, an acute mortality with cannibalism diagnosis was determined. Based upon the acute death of the bird in full production with a crop full of feed and various foreign objects in the gizzard, the primary rule out was zinc heavy metal toxicity followed by other heavy metal toxicity (e.g. lead).
Both cases provide solid examples of the affects foreign metal objects can have on birds. For more information about these two cases, contact Dr. Martin Ficken, TVMDL-Gonzales Resident Director. To learn more about avian testing options, visit or call 1.888.646.5623.
Figure 1 – Gizzard containing metal screw. This protrusion is thought to be the original cause of exudate in the bird in case one.
Figure 2 – Metal screw that was removed from the gizzard of the bird in case one.
Figure 3 – Metal objects, some potentially zinc-coated, that were removed from the lumen of the gizzard of the bird in case two.
Source :