CDS (Cast Deployment System) Gods is right..... For Merch at World Of Disney, we got two(2) 30min breaks per 8.5 hours scheduled (30min paid, 30 unpaid, so you end up w/ 8 hours)
At some point after that... you get 2 30mins and 1 15min break.... and if you work even longer you get 3 30mins breaks....
But in turn, if you work only 6 hours you will only get one 30min break (not sure if it paid or unpaid though).
but each location is diffrent though as not everyone uses CDS. Some places (such as Ride OPS and Lifeguards) do Rotations. you go from spot to spot to spot and end up in a break during the rotation.