|Practical Poultry Raising (Peace Corps, 1981, 225 p.)|
|7. Keeping chickens healthy|
Looking carefully at the body and insides of a chicken that has died of unknown reasons may help discover those reasons. Very sick birds, with no hope of recovery, should be killed, using locally approved methods, or by dislocating their necks.
It will be helpful to examine the insides and outsides of as many healthy chickens as you can when they are slaughtered. Note the position, size, color and texture of all internal organs. Then, when you work on a sick bird, you will be better prepared to spot abnormalities.
This manual will not attempt to give instructions on how to diagnose most diseases - that is best done by special publications with color illustrations - but there are some signs you should look for.
Killing a Chicken. Stretch neck and bend back around thumb.
Examine a bird as soon after death as possible, before body conditions have changed. As you work, take good notes. They will help veterinarians or lab technicians, if they are available, to identify the problem. Ideally, you would take or send a few sick but still living chickens to the vet or lab for diagnosis, but this often is impractical.
In a post mortem, first examine the outside of the bird. Look for lice or mites, particularly around the vent, that may have contributed to the death. Discolored head parts, such as the comb and wattles, are indications of a number of diseases. Straighten the neck, pull the tongue and examine the throat and windpipe for cheesy nodules (lumps), signs of pox. Check the nostrils for a putrid smell. If the legs are rough, scaly and swollen, it may indicate mites. Look for swollen leg and wing joints and excessive abdominal fat. Also look for blackened spots which can be caused by scorpion stings.
Open the bird carefully. With a knife or shears, cut through the side of the mouth and esophagus. Look for the lesions (injured areas) of pox, fungus, excess blood or mucus, and other abnormalities and foreign matter and nodules. Slit the larynx and trachea, looking for excess mucus, inflammation, blood and cheesy matter.
To look inside the bird, first slit the skin over the hip joints and dislocate them so that the body lies flat. Puncture and cut the skin from just below the point of the breastbone to the head. Pull the skin flaps aside to bare the breast. With heavy shears, cut through the heavy bones and ribs on both sides of the keel (center ridge of breastbone), and remove the keel and breast muscle. Do this with care or you will damage the internal organs. Check for fluid in body cavity. In females check body cavity for broken egg yolks (a black fluid if broken yolk has been in body cavity for a while).
Slit the crop, remove food (noting if it smells sour), and examine lining for worms, fungus and other problems. Examine the liver, noting its color (normal is dark brown), and looking for lesions or nodules (soft ones may indicate leukosis). Check the heart for lesions, hemorrhages on the fat, and cheesy matter or fluid inside. Examine the spleen and bronchial tubes for lesions and nodules. Note the color and texture of the lungs (normal, bright red and spongy, will float in water). Look for fluid (pneumonia), tumors, nodules, and congestion (dark red, will sink in water).
Remove the intestines and look for tumors, nodules or hemorrhages. Slit the intestines to check for worms and other problems. Thickened intestinal walls may indicate microscopic worms or coccidiosis. Also look for blood, inflammation and excess mucus. If you find blood in the ceca, look for cheesy matter, scarred lining and cecal worms.
Open the proventriculus (true stomach, located at the joining of the esophagus and gizzard), checking for hemorrhages, worms, or inflammation. Slit the gizzard, looking for erosion. Gizzard erosion most often is caused by a nutritional deficiency and is indicated when ulcers and/or peeling of the gizzard lining is seen. Check the kidneys for urates (white material) in internal passages. Examine the brachial nerves - if swollen, may indicate leukosis. Note gall bladder size and color (normally green). In layers, check the ovary and oviduct for excess fat and ruptures (breaks) that lead egg yolk into other body areas.