2,557. What Is "Deficient?"
Hilchos Shechita 8:1
“Deficient” refers to two organs that render an animal a treifa if it doesn’t have the requisite number, i.e., the lungs and the feet. There are five lobes in a lung. If one drapes them over his hand with the inner part of the lung facing him, three lobes will be on the right and two on the left. Furthermore, on the right there’s a small ear-shaped appendage separate from the lobes, which is in its own “pocket.” This appendage is called the “rose” because of its shape and it’s not considered one of lobes. Therefore, if an animal is missing the rose, it remains permitted. In fact, some animals have it and some others don’t. If the rose is punctured, the animal’s a treifa even though the pocket seals the hole.
Hilchos Shechita 8:2
If the number of lobes is deficient and one is found on the left or two on the right, the animal’s a treifa, but if there are two on the right plus the rose, the animal remains permitted.