Routine tail docking of piglets is widely practiced to prevent tail biting but addresses symptoms rather than root causes of the problem.
Tail docking is painful — it is performed without anesthesia in most commercial settings. While the pain is acute and time-limited, it reflects a system in which the environment is too poor to keep pigs with intact tails. The solution to tail biting is improving the environment, not removing the tail. This is both a direct welfare issue and a proxy for the broader quality of the housing system.