Actually, leghorn hens are supposed to have combs that hang over to one side, and roosters combs are supposed to stand up straight.
Ok, hatchery vs show birds. To start off hatchery birds tend to come from places that raises birds to make a profit, whereas show birds tend to come from people who raise birds for a hobby.
Hatchery birds are mass produced in large numbers to fill orders and are sent off as chicks (way before the age when you can tell good show quality from non-show quality). To a certain degree this is a lot like a puppy mill that mass produces puppies to fill pet stores. Keep in mind though that hatchery birds are usually perfectly healthy, happy, productive chickens, unlike puppies form puppy mills.
The Standard of Perfection is the book that defines what makes each breed unique from each other. Show birds have been bred to conform as closely as possible to this standard in both looks and production levels. Mind you, sometimes production levels slip in show bids, whereas looks slip in hatchery birds. The best breeders try to have a good balance both.
It's quite possible your leghorn could have had a disqualifying feature that the judge ignored and placed you anyway. I've seen this happen when new exhibitors show. The judge does not wish to disqualify the bird and disappoint the new exhibitor, so they place them in the class. Mind you, for us experiences show people we would have had are butts DQ'd in an instant
Urban Coyote
P.S: Just an interesting note, Australian show leghorns looks very different from North American show birds.