Is it commonly thought then that all mammals (pigs, horses, whatever) were simpler in intelligence thousands of years ago than today? In other words, our modern day sheep are much more intelligent than they were a few thousand years ago? Every animal is evolving smarter in their intellect? 30,000 years ago did we have a bunch of dumb animals? And 30,000 years from now, if they're still around, sheep will be much more intelligent?
Is it commonly thought then that all mammals (pigs, horses, whatever) were simpler in intelligence thousands of years ago than today? In other words, our modern day sheep are much more intelligent than they were a few thousand years ago? Every animal is evolving smarter in their intellect? 30,000 years ago did we have a bunch of dumb animals? And 30,000 years from now, if they're still around, sheep will be much more intelligent?
Well first, most of the time a few thousand years isn't going to cover a great deal of evolutionary change. You should look at much larger time spans to get a more "big picture" view.
But the primary point is that beyond a certain point, intelligence isn't that critical for a lot of animal species, and for those animals evolutionary pressures will likely be at work honing *other* abilities, not "IQ". For early humans, however, intelligence *was* more critical to our survival, and thus we "specialized" in better brains while cheetahs, for example, specialized in being fast enough to better outrun their prey. There's not just one "success strategy" in all of nature -- different species "specialize" in different abilities.
Often there are real tradeoffs. For example, blind cave fish are blind not only because they no longer need their eyes (since they live in darkness), but because a quirk in their biochemistry makes it so that by losing their eyes, they are able to smell better -- which is obviously a big help in a lightless environment. Their cousin species which still live in the open, however, are better off keeping their eyes, and getting by with a less acute sense of smell. There's a trade-off between the two senses, and which balance evolution achieves along the possible continiuum of the trade-off depends strongly on the exact needs of the species, and that depends heavily on its current environment.
Actually, sheep will probably be less intelligent, if they are still domesticated. They don't need intelligence, if we are protecting them from predators.