I had the same issue, but with my neighbour's sheep. Problem was solved pretty cheap, fast and easy (even if temporary, already 2 years in place but planning to make a more permanent one in the spring). Every 4-5 meters I put a wooden pole and between them low-weight fence (here it is called Rabitz,
https://www.google.com/search?q=rabitz ). Costed around 40 usd / 100 meters and just few hours of work. I know it is temporary, but if you want it fast done "yesterday" it is a solution.