274 dogs were used in the making of this movie which is the world record for the most dogs used in a feature film.
All of the untrained dogs appearing on film are mixed breeds adopted from animal shelters.
Hagen is portrayed by twin dogs Luke and Body. They were found in a caravan park in Arizona just as their owner was about to take them to an animal shelter.
Official submission of Hungary to the best foreign language film category of the 87th Academy Awards 2015.
All dogs that were used in the film (other than the two trained actor dogs that played Hagen) had been from local shelters and went through training for the film. 280 canines were used (according to the producer). By the end of the film, because the dogs were all over the streets with individual trainers all the time during filming, they all found homes.