2,558. Reversed Lobes; Extra Lobes

Hilchos Shechita 8:3

If the lobes were reversed so that there were three on the left and two on the right with no rose – or if the rose was with the three on the left side – then the animal’s a treifa because it’s deficient on the right.

Hilchos Shechita 8:4

Let’s say the number of lobes increases. If the extra lobe is on the side with the usual lobes or in front of the lungs on the heart side, the animal is permitted. If it’s on the back near the ribs, the animal’s a treifa because an extra organ is the same in halacha as a missing organ. This is the case so long as the extra lobe is the size of a myrtle leaf; smaller than this isn’t considered a lobe and the animal remains permitted.