18th Century Sheep

There is truly a genetic difference between the breeds of sheep we commonly see at historic sites (Leicester Long Wools, Hogg Island, etc.) and the more modern breeds. The last few visits to historic areas with sheep show them grazing calmly in the field, paying only scant attention to the worm fences that contained them. Fences with spaces large enough to toss a 5 year old through. At my house, however, I can't keep the sheep from busting down a vinyl coated galvanized wire fence, between their pasture and the turkey pasture. Why? Do they really feel a need for some quality time with the poultry? Is turkey chow really that much better than grass? I think it's just a criminal gene embedded in the Polypay breed that was developed in the 1970s. After fixing the fence several times, making it tighter each time, I finally pulled the fence tight and secured it with a piece of chain. I'm not making any bet's though, 'cause I found a set of bolt cutters in the sheep's barn, hidden under six inches of hay....