Many dogs are placed in shelters or end up on the streets as a result of poor training on the owner's part. Dogs need proper training and direction. Most problems with dogs can be prevented if proper direction is taken from the beginning. Invest a little of your time now and and it will result in a lifetime of enjoyment for you and your canine companion. Dogs are pack animals by nature and prefer a dark, small, den-like atmosphere as opposed to a huge open room that we humans would enjoy.
Dog crates are simply a rectangular structure just big enough for the dog to lay down in.
They should NOT be large enough for the dog to play in. The natural tendency to stay clean is basic instinct. The crate becomes the den that humans took away when we domesticated dogs thousands of years ago. Crates are primarily used for house breaking puppies. Crates are not cruel by any stretch of the imagination.