I looked it up because I had not heard that term....wow....Wikipedia is where I went ...not like it is an official source tho.....
Bait animals
"Bait" animals are used to test a dog's fighting instinct, and these animals are often mauled or killed in the process.[citation needed] Trainers obtain bait animals from several sources: wild or feral animals, animals obtained from a shelter, or in some cases, stolen pets.[7] Sometimes the animals are also obtained through "free to a good home" ads. According to news reports compiled by the National Humane Society, the snouts of bait dogs are wrapped with duct tape to prevent them from injuring dogs being trained for fighting. Other animals, such as cats and rabbits are also reported to be used as bait animals.[citation needed] Experts have said small dogs, kittens, and rabbits are more at risk of being stolen for bait than larger animals.[citation needed]
The real idea of baiting is to place an object, any object that will keep the dogs focus on it and place it in front of them while they are on a treadmill being conditioned for their match. The benefit of this is that it keeps the dog running longer than it would normally without the bait.
edited to ad where I got info