Three must shave and their shaving is a mitz-vah: a nazir, and a metzora, and the Levi’im. If these [three] shaved without a razor, or if they left two hairs, they have accomplished nothing.

Preferably, the two birds should be identical in appearance, height, and monetary value, and they should be acquired at the same time. Even if they are not identical, they may be used. [If] he purchased one [bird] one day and the other [bird] the next, they may be used. [If] the first bird was slaughtered and was found to be a non-wild bird, he should acquire a mate for the second; the first one may be eaten. [If] he slaughtered [the first bird] and it was found to be tereifah, he should acquire a mate for the second; it is permitted to benefit from the first one. [If] the blood spilled, the bird that should have been sent away is left to die. If the bird that should have been sent away dies, the blood [of the slaughtered bird] must be spilled out.