Penguin sweaters, also known as penguin jumpers  are sweaters which are knitted for penguins that are caught in oil slicks. When an oil spill affects penguins they are dressed in knitted sweaters to stop them preening their feathers and to keep them warm, since the spilled oil destroys their natural oils. This prevents them poisoning themselves by ingesting the oil. The sweaters are removed and discarded as soon as the penguins can be washed.
This term is also used for sweaters made from penguins.
Similar garments are being made for battery-powered chicken rehabilitation.