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Crate training will have many benefits for your bulldog, including protecting him from household hazards and reducing his separation anxiety. To begin crate training, you will need to select the right-sized crate for your bulldog. It should be either 24 x 30 inches (61 x 76 cm) or 24 x 36 inches (61 x 91 cm) for a French bulldog, and either 42 x 30 inches (107 x 76 cm) or 42 x 36 inches (107 x 91 cm) for an American bulldog.  Your bulldog should be able to sit, stand, and lie down easily in the crate, but not have enough space to create a bathroom area.  If you have a puppy, consider purchasing a crate with an adjustable divider. This will allow you to increase the crate space as your puppy grows into an adult. The crate should be a place of safety and comfort for your bulldog. The more welcoming it feels to him, the more likely he’ll want to spend time inside of it. Place his favorite blanket and toys in the crate. You can also place a quilt or sheet over the crate to make it feel like a cozy den. In addition, place his food and water bowls in the crate. Since bulldogs are motivated by food, place some food in your bulldog’s bowl or on the crate floor to encourage him to enter the crate. A bowl would preferable, since he wouldn't be able to pull it out of the crate very easily. Whenever he enters the crate, give him lots of verbal praise—this will teach him that going inside his crate is a good thing.  Leave the door open during the early stages of crate training so he can explore the crate at his leisure. Consider giving him a verbal command, such as ‘crate,’ to enter the crate. Immediately give him a treat and verbal praise when he enters the crate after your command. Once your bulldog is comfortable entering the crate on his own, work on closing its door behind him. Start with closing the door for only a few seconds and then letting him out. If he starts whining or crying, wait until he calms down before opening the door. When he can handle a few seconds, close the door, leave the room, and return after random lengths of time (e.g., 2 minutes, 5 minutes).  Opening the door only when he is calm will teach him not to use whining and crying to get your attention while he is in the crate. Remember that puppies cannot hold their bladders for very long, so you should not leave your puppy bulldog in the crate for long time periods. Until 12 months of age, puppies can hold their bladders for about 1 hour per month of age.  When you are home, spend time with your bulldog while he is in the crate. Bulldogs are friendly and sociable dogs; interacting with your bulldog will keep him from getting lonely. Always remember that the crate is a place of safety and comfort, not punishment. No matter how frustrated you get with your bulldog, especially if he has misbehaved, never send him to his crate to punish him. Your bulldog should always have a positive association with the crate.

Summary:
Purchase a crate. Make the crate feel like home to your bulldog. Encourage your bulldog to explore the crate. Practice leaving your bulldog in the crate. Do not use the crate as punishment.