As I am from Australia I cannot comment on what happens in the US programs. We do not test dogs before placement as all dogs are bred and incredibly carefully socialised on campus, to the point that we have a 10 year waiting list for certain aspects of this puppy nurting program. All pups are handled by at least five new people every day from 10 days of age to 8 weeks, and this includes people of all nationalities, ages, genders, etc, etc. Other breeds of dogs are introduced to them at 5 weeks of age, including non guide dogs, through very carefully selected and health checked dogs of volunteers and staff. They have a cat living on campus that has free roam during the day and is bought into their playroom each day from 3 weeks of age. They spend time on any manner of different services, not just household ones, but also stones, cobblestones, concrete, ashphalt, sand, dirt, tanbark, etc, etc. They are introduced to wearing collars at 5 weeks of age and begin learing to walk on a lead at 6 weeks of age. Within 2 days of being on solid food they eating out of individually named bowls and by 6 weeks of age they know to sit to wait for the bowl to be put down before they begin to eat. They have began toileting on command, and know the the then commands the puppy raiers will use with them. They know to toilet outside, but will if desperate use a piece of artifical grass inside if they need to. There mother is able to come and go from them at will through special doors. The puppy raisers do continue the socialisiation but their primary aim initially is to teach the pup to walk on a lead without sniffing anything at all. Only when it can do that in the community, will it begin to enter public places and then only when the full attention of the puppy raiser can be given to the pup. The aim of the puppy raisiing progarm is to proof the pups in the comman they learnt while with their littermates and mom.
All of the dogs are allowed to chase after toys and are encouraged as a natural form of play, but the puppy raisers are discoruaged from using balls (specifically tennis balls) because they are what the dogs are more likely to see on the street. Hence the pups chase after and can fetch other toys, just not balls. They do not test the retrieve when the dogs are bought back in for temeprament testing. Hence my dog was chasing after toys at a very young age, even before the puppy raising stage and still continues to do so, but she has never bothered to bring one back to me, it just seems pointless to her!! I have to some degree been able to train her, but the motivation is simply not there for her, and in play she would simply not consider it, to her it is not fun. I have witnessed kennel staff and trainers throwing toys for dogs at all ages and stages of the training process, from very young pups right up to working guide dogs.
All dogs spend at least two weeks in the kennels at about 6 months of age, but this will be held back for bitches as they are all kennelled during all heat cycles. All dogs are in yards the size of basketball courts in groups of 4 during the day, inslugin those in training. The have trampoline beds, toys and volunteers who play and pet, them, etc. THey spend at least one hour each day in a large grass filed the size of a football field each day and also one hour in a angility yard just playiing and having fun. They are walked on lead by volunteers each day as well as speding the hour with a trainer each day. overnight they are in kennels the size fo a toilet cubical with one other dogs, except for bithcehs in heat who sleep in the whelpging boxes each heat cycles aloene, so that if they do become breeders it becomes a comfortable and second home to her. Breedign bitches are bought in 10 days before they are due to whlep and have extra massages and the like as this has been found to hlep the pups in future. All pus are handled from birth and have stimulation carefuly done from vet nurses Itechs) fro the moment they are born, as well as introducing them to many household sounds, etc, etc.