![A sacciform blind pouch occurring after attachment of the intestinal wall to an unabsorbed yolk sac, causing impaction.](http://www.thepoultrysite.com/publications/images/image_Page_100_Image_0005.jpg)
546.A sacciform blind pouch occurring after attachment of the intestinal wall to an unabsorbed yolk sac, causing impaction.
![. INVAGINATION. Involvement of anterior parts of the small intestine, the mesentery and the tops of the caecum into the ileum. Usually, it occurs with a strong intestinal peristalsis, often following ingestion of feed after a restrictive feeding regimen.](http://www.thepoultrysite.com/publications/images/image_Page_100_Image_0006.jpg)
547.. INVAGINATION. Involvement of anterior parts of the small intestine, the mesentery and the tops of the caecum into the ileum. Usually, it occurs with a strong intestinal peristalsis, often following ingestion of feed after a restrictive feeding regimen.
![Rotation of the small intestine on the longitudinal axis of the mesentery, resulting in venous stasis and necrosis of the intestinal wall.](http://www.thepoultrysite.com/publications/images/image_Page_101_Image_0003.jpg)
548.Rotation of the small intestine on the longitudinal axis of the mesentery, resulting in venous stasis and necrosis of the intestinal wall.
![CROP IMPACTION. It is caused by hard, fibrous feed or litter, whose accumulation results in impaction.](http://www.thepoultrysite.com/publications/images/image_Page_101_Image_0001.jpg)
549.CROP IMPACTION. It is caused by hard, fibrous feed or litter, whose accumulation results in impaction.
![CROP IMPACTION. The retained content into the crop sometimes causes putrefactive necrotic processes, affecting the crop wall and the covering skin.](http://www.thepoultrysite.com/publications/images/image_Page_101_Image_0002.jpg)
550.CROP IMPACTION. The retained content into the crop sometimes causes putrefactive necrotic processes, affecting the crop wall and the covering skin.