Given those two facts, it is unrealistic for us to think that we can break this instinct. Greyhounds love to run and need to have some boundaries in place. A new greyhound can be overwhelmed by the wide open space of a backyard and given the chance to take off, they probably will. Greyhounds have lived such an isolated life at the track that they don't know what cars are, or to look out for them on a street. We can never trust our dogs outside of a fence without a leash.
Greyhounds wear muzzles when they race to protect one another from snapping.
Running to win is the only purpose in life for a racing greyhound and they become very competitive at that time. Therefore, when we get our retired racers together for a fun-run, it's necessary to muzzle them when they are running. Muzzles are also recommended when introducing them to small animals for the first time. Greyhounds are kept on a very strict schedule at the race track and are let out four times a day. Keeping them on a schedule is helpful in housebreaking, as is positive reinforcement.