Sense
Magnetoception (or magnetoreception) is the ability to detect the direction one is facing based on the Earth's magnetic field. Directional awareness is most commonly observed in birds, which rely on their magnetic sense to navigate during migration. It has also been observed in insects such as bees. Cattle make use of magnetoception to align themselves in a north-south direction. Magnetotactic bacteria build miniature magnets inside themselves and use them to determine their orientation relative to the Earth's magnetic field.
Feather pecking
It has been shown that domestic hens have iron mineral deposits in the dendrites in the upper beak and are capable of magnetoreception. Because hens use directional information from the magnetic field of the earth to orient in relatively small areas, this raises the possibility that beak-trimming impairs the ability of hens to orient in extensive systems, or move in and out of buildings in free-range systems.