The farm is an adequate laboratory as any--at least you don't have some Piled High and Deeper grubbing for a grant...
I find the stories of the breeding of domestic sheep and goats to be far more compelling an argument against speiciation than even the breed-variety in dogs, because this breeding has been going on for far longer (thousands of years, a generation a year), with far wider geographical isolation, and with more interesting results. Due to an interest in textiles and small-scale farming, I'm familiar with a wide variety of breeds of sheep and goats.
The Merino sheep, bred for wool and only incidentally for meat, has a skin with deep folds--there's a lot more skin on a Merino than on a meat sheep, which makes for many more follicles and much more wool! But the Merino is hard to shear--you risk nicking all that skin. Meat sheep are bred for twinning, with all the complications and benefits that causes the shepherd. Most modern domesticated sheep breeds can no longer shed their wool. If they are not shorn regularly, they will die from the weight and burden of the long wool.
There is a breed of goat, the Nubian, which has large ears to act as a kind of air-conditioner in hot climes (India). It is also the breed with the highest butterfat content in its milk. There is a goat bred for the alpine that has no ears at all!--which means those ears can't freeze off.. The little tempermental Angora goat, looking for all the world like a poodle and very much a diva, has long silky white curls which provide our mohair. <"Mom, what's a 'mo'?)
Goats bred in India, goats bred in the Alps, sheep in Iceland and sheep in the Holy Land. All the same goat--all the same sheep. No new species.
As I've noted several times on threads such as these, the best argument in favor of Intelligent Design (as a general principle) is that we humans have practiced it for thousands of years. Yours are among the best specific examples I've seen.
Most modern domesticated sheep breeds can no longer shed their wool. If they are not shorn regularly, they will die from the weight and burden of the long wool.
A recent example from the news: Shrek, captured after six years on the run, before being shorn.