Crop: The crop is an out-pocketing of the esophagus and is located just outside the body cavity in the neck region (see Figure 3.3). Consumed feed and water are stored in the crop until the remainder of the digestive tract is ready to receive more feed. When empty, or nearly empty, the crop sends hunger signals to the brain so that more feed is consumed. Although the mouth excretes the digestive enzyme amylase, very little, if any, digestion takes place in the crop – it is simply a temporary storage pouch that evolved for prey birds which need to move to the open to feed. They are able to consume relatively large quantities of food rapidly and then return to a more secure location to digest it. Occasionally the crop becomes impacted (crop impaction, also referred to as crop binding or pendulose crop). This may occur when feed is withheld for a period of time, causing chickens to eat too much too fast when the feed is returned. A crop may also become impacted in a chicken that is free-ranged on a pasture of tough, fibrous vegetation. With a crop impaction, even if a chicken continues to eat, the feed can not get past the impacted crop. The swollen crop may also cut off the windpipe, suffocating the chicken. Crop impaction is unlikely to occur in properly fed broiler or broiler breeders.