all pups r different there is no sett age,i would normally ave my pups travelling empty burrows from around 10 months them let them c plenty of action but dont let them in on it till u think ther not pups anymore,i have dug pups as young as 12/14 months old but on the other hand ive had dogs that havent done anything until they were 2 an a half its all about knowing when ur pup is ready