
Hi,
It is a good idea to stick with the '5-minute rule' when exercising puppies: walks of 5 minutes for every month of their age. So a three-month puppy would be out for about 15 minutes at a time. In your situation I would take the pup over to the field for 15 minutes play, off lead, once a day (if you keep walking about he'll want to stick with you so you have lots of opportunity to practice recall!), but I would also take him out another couple of times for lead training and socialising. He needs to see and become blase about anything and everything you can think of - livestock, other dogs, children, cars, bicycles, men with beards, women with hats, wheelchairs, lorries, umbrellas, buses .... anything he might meet in his life.
:)