Leviticus 5:8 "He shall pinch off its head close by its neck, but shall not divide it in two"

HaShem designed a special process for preparing a bird brought as a sin-offering.

Instead of slaughtering it with a knife, part of this procedure requires the priest to cut off the bird's flow of life from the back of its neck, by pinching or squeezing it.

This process is called "Melikah".

This Negative Mitzvah cautions the priest not to separate the bird's head from the rest of its body when he is preparing it for a sacrifice.