When do Bearded Collies stop growing?

Bearded Collies stop growing around 18 months of age. Most of their height growth occurs in the first year, but they may continue to fill out and gain muscle until they are about 18 months old. 

You can transition a Bearded Collie to adult dog food around 10 to 12 months of age when they have reached most of their growth milestones. Adult dog food will provide the nutrients needed to maintain their health as they mature.