This could be the reason she was in the kennels mate? Do you know anyone who has a farm where you can walk near the sheep and correct the behaviour manually whilst on a long line? The obedience needs to be sorted before allowing her free run. use a long line, use her new name at all times during feeding, patting each time she looks at you, this all teaches them quickly.
the punishment when around sheep must be swift and timed right, as tempting as it is, giving her a hiding 20 mins after she's already run off is of no use, the correction has to be when she looks at the sheep, as her body lang