Lamb inhabits a sleepy corner of the meat business in America, with far fewer sales than chicken, beef or pork and often raised by small producers. It is popular, however, among growing demographic groups like Latinos and Muslims, and some consumers who eat lamb because they believe the animals are raised more humanely, far from feedlots and the practices of large-scale meat production.

Now an animal rights group, Compassion Over Killing, has produced a video that it says shows repeated abuse of sheep at a California processing plant owned by the nation’s largest lamb producer.

The approximately four-minute video was shot from May through November at a plant in Dixon, Calif., owned by Superior Farms, which sells to retail chains like Walmart and Kroger. It shows, among other things, a sheep struggling as a worker slices repeatedly at its carotid artery with a knife; some animals appear to continue breathing after their throats have been slit.

In another segment, a worker from a trucking company that delivers live animals to the plant repeatedly stabs an electric prod into a truck in an apparent effort to get the sheep inside to move. The video also shows workers changing “best by” dates on packages of lamb.