Little data is available on the number of dogs that go to foster care versus a shelter. However, if a pet is in foster care, the person interested in adopting the pet is informed of this fact by the volunteer from the rescue group. In many cases, the person adopting the pet also meets the foster family.
When a person adopts a dog from a shelter, he can visit the shelter and choose one of the dogs there. If he is instead interested in adopting a dog that is in foster care, he can look at pictures of the dogs online or talk with volunteers from the rescue group about the type of dog he wants.
When a dog is with a foster family, the foster family has a good sense of whether or not the dog is good with children or friendly with other pets. This information can be useful during the adoption process.
There are many different types of shelters. Some no-kill shelters refuse to kill the pets they house, while other shelters have relatively high kill rates. Rescue groups work with no-kill shelters or on their own, and rescue animals from unfortunate situations or from shelters where the animals are going to be killed.