When Californian Regina Collins picked up her 12-week-old puppy, Chance, after being boarded and trained at Ridley K9 Academy, he was afraid to come to her. She demanded that owner/trainer Garrett Ridley tell her what he had done to her puppy; she was informed that she shouldn't approach him because he was "in trouble."
A vet examination revealed that Chance was covered in urine, dehydrated, and his eyes were hemoraging. The latter is usually caused by being restrained at the neck or high pressure around the neck.
This is why it's so important to interview potential boarding facilities. What kind of training methods do they use? Can they give you client references? Ask to tour the facility and see the staff engaged with the dogs. How are the dogs responding? Do they seem relaxed, stressed, scared?
Of course, if you are not welcome to visit behind the scenes, you are better off boarding elsewhere. Better yet, find a petsitter so your dog can relax in familiar surroundings and take a training class with your dog when you return so you can both learn and strengthen your bond.