The UK Department for Environment, Food and Rural Affairs has published a document on beak trimming subsequent to the adoption of welfare regulations, effective Jan. 1. 

For general purposes, chicks can be trimmed before ten days of age using infrared equipment providing that not more than one-third of the beak is removed. Under exceptional conditions, such as when outbreaks of pecking and cannibalism occur, flocks can be beak-trimmed “as a last resort.”


The details of the regulations can be accessed at DEFRA's website