That's definitely NOT pecking damage. That's weasel or rat damage. A weasel or rat can get through a 1" space. If a chick's head can fit through, a weasel can get in.
Neck damage is characteristic of a weasel or rat. It's not characteristic of pecking damage, which is usually at the base of the tail.
Neck damage is characteristic of a weasel or rat. It's not characteristic of pecking damage, which is usually at the base of the tail.