The film features the eight 'named' sheep (Shaun, Timmy, Timmy's mum, Hazel, Shirley, Nuts and The Twins), however, a few minutes in as they are celebrating the success of their plan to make the farmer fall asleep in the wheelbarrow a ninth sheep (which looks like another Hazel) appears for that scene only.
When Trumper shoots his taser while chasing the cloth animal that contains all of the sheep, it wraps around one of the hind legs. But later on it's shown wrapped around all 4 legs.
When Shaun and the rest of the flock are locking the farmer in the trailer, he grabs a pair of blue headphones from the seat of the tractor and puts them on the framer. Once they have locked him inside, Shaun is then seen wearing the same pair of headphones and operating the tractor.