Thanks for the input. I'll probably just say it dates to mid-18th century or earlier.

As for the other selections, it's been a fun challenge. As it's a very general audience, I wanted a combination of familiar and unfamiliar, plus a couple for the kiddies.

General sheep-farming songs:
From the Lambing to the Wool (Judy Small)
Now I'm Easy (Eric Bogle)
Broom of the Cowdenknowes
Waltzing Matilda

More specific to the processes:
Click Go the Shears
Tarry Wool
Spinning Wheel

Children's songs:
Baa Baa Black Sheep
Mary Had a Little Lamb

I would have liked to pin down a weaving song, but time was limited and I could only learn so many new songs in the time.