Crate training is the process of teaching a dog to go into its crate on command and to be comfortable there while enclosed. Dogs, like all canines, are den-dwelling animals by instinct and some claim that a crate becomes a den substitute, providing a familiar and safe haven for the dog and that a crate-trained dog benefits the dog and the dog's owner in a number of ways.

Housebreaking
A crate can be used as an adjunct to housebreaking puppies. By instinct, most dogs do not want to defecate or urinate in their den -- in this case, the crate.

The puppy is kept in the crate except during feeding time or during supervised play time. When the puppy comes out of the crate, he or she is taken to the soiling area and given encouragement to "go potty" or other predetermined voice command. When the puppy "goes potty" she or he is profusely praised. Until housebroken, the puppy is either in the crate or is closely supervised.

For maximum effectiveness, the crate must be just large enough for the puppy to be able to stand up, turn around, and lie down comfortably. If there is too much space, the puppy might use the unoccupied end as a bathroom. In addition, timing of the puppy's potty breaks are crucial. Even a confined puppy has a difficult time controlling its urination and defecation. Control gets better as the puppy gets older, but it is the owner's responsibility to ensure that the puppy has ample opportunities to eliminate outside the crate.

Toys and soft material for bedding in the crate make it more comforting for a dog or puppy.

Even an adult dog, when ill or affected by certain medications, can end up soiling the crate, making the dog uncomfortable both physically and mentally, if the owner isn't vigilant and aware of the dog's needs.

It is important not to misuse the crate by turning it into a prison. Sensible trainers advise only to close the crate when the owner is home. Simple confinement is not the same as crate training. The crate is not designed for locking the dog in and leaving him for extended periods; if the dog isn't let out when it needs to relieve itself the training will be set back weeks or even months. To avoid this, make a diary of your puppy's frequency of toiletting when not confined, then make sure he is taken from his crate to your designated toilet area at these intervals. Being in a crate will not mean he needs to toilet less frequently! No dog should ever be confined to a crate for a longer period than their owner can 'hang on' without needing to use the lavatory.

Away from home
All veterinary clinics and hospitals keep dogs in crates when the dog must stay for observation or care. A dog who understands the concept of a crate is much less likely to become stressed during medical care and is much easier for the staff to handle when putting him into the crate or removing him.

The same is true for kennels, where an owner might leave a dog while out of town or during emergencies. In true emergencies, such as when an owner's home is destroyed or damaged by wildfires, floods, or earthquakes, a dog who understands and is comfortable in a crate is much easier to manage while the owner is performing other tasks or while the dog must be left in someone else's care in a situation that is also likely to be stressful to the dog and make an unconfined dog more likely to try to escape.

Control at home
A crate-trained dog feels safe and comfortable in its familiar crate at home. The crate should always be a pleasurable experience for your puppy. When guests visit, when small children are present unattended, when construction occurs in the home, or in myriad other circumstances, it is convenient to be able to put the dog into its crate, where it can relax and sleep, unattended for short periods, and the owner can also relax in the knowledge that the dog will not be harmed, will not cause problems, and will not escape out an inadvertently open door. A crate with very see-through sides, such as a wire crate, can be made to feel more safe and enclosed by draping a towel or sheet over it. Again, the dog must not be confined for long periods.

Travel by air
When a dog travels on an airline, he must be enclosed in a sturdy crate. Because travel is stressful for the dog to begin with, as is separation from its owner, a dog who is in a familiar and comfortable crate has a tremendous advantage over a dog who must be forced into an unfamiliar crate along with all the other stresses of travel.

Travel by automobile
When a dog travels by car, a loose dog can create several hazards for itself or its human companions. For example:

An excitable dog who sees another animal outside the vehicle might leap into the driver's lap while the car is moving, potentially causing an accident.  Dogs have been known to leap through the window of moving cars, injuring or killing themselves.

A loose dog barking at a stranger who comes up to the car (such as a police officer) can pose a hazard to the stranger or to itself, as in the case of Leo, the Bichon Frise, who was grabbed and thrown into moving traffic in an incident of road rage in San Jose, California in 2001, drawing tremendous media attention and resulting in the man's conviction for the dog's death.

Drivers who are distracted by their dogs moving around behind them, barking, or getting into forbidden things while the car is moving can also cause accidents, such as the one that nearly killed writer Stephen King. A British Royal Auto Club survey showed that 11 percent of drivers listed dogs moving around in the car as distractions that they had experienced while driving.

In the event of an accident, even a well-behaved dog can become a dangerous projectile that can seriously injure the driver or passengers in seats in front of the dog.
Even if the dog doesn't hit a person during an accident, the dog itself can be severely injured or killed, for example by being thrown through the windshield when a car going 60 MPH abruptly crashes and stops, or can be thrown from a tumbling car.

If the dog is only moderately injured or uninjured, and particularly if the owner is injured, a loose dog might consider people coming to the owner's aid to be the causes of the accident or threats to its family or property and might attack or attempt to drive off the helpers.

For all the reasons that humans and children must be securely fastened in their seats, dogs also should be. A crate that is securely strapped into the car provides an easy method to contain the dog that still allows the dog to move comfortably during travel.

Training
Crate training usually involves rewarding the dog for entering the crate and for remaining there, using the crate as part of a play session, feeding the dog in the crate, allowing the dog to explore and use the crate until it is no longer intimidating, and so on. This is only a summary of detailed techniques.

Rules to live by when crate training: Source - Gun Dogs Online

- The crate should never be used to punish your dog.
- Keep the introduction to the crate short and sweet. Let the dog get comfortable with the crate before attempting to close the door on him. Once you close the door, reward him with praise and/or a treat. Keep the first few sessions with the door shut short. Ten seconds without crying is what you're striving for. Open the door and give him lots of love and praise. Slowly, and I mean slowly, increase the time with the door shut.
- Select the proper size crate for your dog. If you buy a crate that is large enough to accommodate him when he is full-sized, block off an area inside the crate to make it just large enough for him to stand up and turn around. Making it too large will allow him to soil one area and live in the other.
- Pick up your dog's water 3-4 hours before putting him up for the night.
- Allow your dog to eliminate completely prior to being put up for the night.
- Take him outside immediately upon letting him out of the crate. With puppies, you may have to carry them outside to avoid accidents.
- Let him naturally find the crate in your kitchen, living room or wherever you decide the crate will reside. Make sure you place the crate in an area well circulated, free of drafts, and out of direct sunlight. Placing food in the back of the crate will encourage your pet to explore and enter this new area.
- Never let your dog out of the crate if he is crying.
- Have a vigorous play session before going to bed.
- An undergarment or a ticking alarm clock can comfort a new puppy during his first few nights away from his littermates.
- Never disturb your dog when he seeks solitude in his crate. Remember this is his domestic den and like you, he needs valuable time alone.
- Finally, be patient and committed to the process.