The activists were from the Brighton branch of global animal protection network Direct Action Everywhere (DxE).
More than 30 activists took part in the action, in Tesco on Church Road, standing in front of the meat aisle, holding pictures of animals with the words: "I want to live."
They wore black tape over their mouths to symbolize how animals' voices are silenced and ignored within farming.
"Our first DxE action went super well today," a member wrote on the group's Facebook page. "We remembered the animals whose dead bodies laid across the supermarket shelves.
"We stayed in the shop for 30 minutes reminding the public of the suffering involved in the animal products they were about to buy. It's not food, it's violence."
Murder and pain
A photo from the action was captioned: "Standing in front of the graveyard. Silence. Unable to speak A chickens broken body wrapped in plastic.
"To most, this is a delicious dinner. To us, this is a horrific scene. This is suffering. This is pain. This is murder.
"This is the animal exploiting industry. Please do not support it."
Find out more about DxE Brighton here