OBSTRUCTION OF CROP IN BIRDS— HARD CROP 139 



Medical.— Before administering medicinal agents it is 

 necessary to thoroughly empty the crop which is done in the 

 following manner: The bird is held with its head pendant, 

 and the crop carefully manipulated and compressed between 

 the thumb and fingers, when the contents will flow out via 

 mouth. The crop should be thoroughly compressed from 

 behind toward the mouth until it is completely emptied. 

 Ten to 30 c.c. of a bicarbonate of soda solution (2 per cent.) 

 is then administered to neutralize the acidity of the retained 

 contents and to dissolve the accumulated mucus from the 

 membrane. For a few days small doses of sodium bicar- 

 bonate (0.15) or bismuth subnitrate (0.10) may be admin- 

 istered daily. Only small quantities of food should be 

 allowed for at least four to five days. 



OBSTRUCTION OF THE CROP IN BIRDS. HARD CROP. 



Definition.— An impaction of the crop. 



Etiology. —The obstruction of the crop is often seen from 

 overfeeding, especially with dry foods (oats, rye, corn, peas, 

 etc.) or with quantities of straw, leaves, grasses, and other 

 indigestible substances swallowed by the bird. In water 

 birds it occurs from eating large quantities of certain grasses 

 (triticum repens, etc.) . Turkeys are most commonly affected 

 by eating large quantities of insects (grasshoppers, etc.), 

 straw, grains and grasses. Further, swallowing various kinds 

 of foreign bodies with the food (metallic substances, large 

 stones, pieces of glass, bones, egg shells, or large numbers of 

 very small stones, etc.) often produces impaction of the crop. 



In some mild cases of catarrh with irritation of the mucous 

 membrane the birds often eat large quantities of indigestible 

 substances leading to an impaction. Animal parasites when 

 in large numbers will produce the same result. 



Symptoms.— The birds are dull, stupid, show rough plu- 

 mage, pale comb and wattles, with a constant opening and 

 closing of the beak; or the beak is held open to facilitate 

 breathing which is often interfered with by pressure of the 

 enlarged crop upon the trachea. A disagreeable odor ema- 

 nates from the mouth, and often quantities of fermented or 



