The number one goal of an animal shelter is to make sure pets go to good homes; ideally "forever" homes. If they did not require people to go through an application and screening process many of the pets adopted out would not find good homes. Even with everything in place there is no guarantee that a pet will find a good forever home.
Sometimes people come to an animal shelter on a whim or with limited information in regards to the pet they want to adopt. The animal shelter asks questions so they can offer tips and advice and perhaps steer the people in a better direction in terms of what pet to get. As such if a person comes to adopt a dog, for example, the animal shelter uses the screening process to make sure the people are aware of just how much exercise, grooming, training, and so forth, that a particular dog needs in terms of making sure the dog is suitable for the people.
|Dog and owner at park, photo by author|
Additionally animal shelters screen people to make sure they can own a pet. Some people rent properties where pets are not allowed, if caught the pet can be confiscated. Some people do not have fenced yards and in some areas it is illegal to keep dogs on chains so the animal shelter must make sure the dogs only go to responsible, prepared, homes.
Animal shelters have questionnaires and contracts because they are adopting pets out, not unlike when human children are adopted out. Animal shelters do not sell pets, they actually care about who gets the pet and they care about that pet's life after it leaves the shelter.
If you are looking for a new pet, be it a cat, dog, bird, or other exotic pet, always check your local animal shelter first. The adoption process can take an hour, or more, by the time you select your pet, apply, and complete the adoption process, so you should go early in the day.