In reply to Timmd:
Correct. If it was the L District (?) program on this past week, iirc, Border Leicester sheep, (I wasn’t paying attention but tv was on in background) prominent white head with long ears held high would have been highlighted by darkening the wool, as characteristics much sought after in the breed, and contrast against it’s long solid body. The whiteness of it’s wool is natural, and sought after, but any colouring will revert to that quickly so not important for selling. If it was all white the head and ears. and a sturdy solid neck, wouldn’t have stood out as obviously.
There are a lot of different reasons why sheep wool are dyed. If animals are sold as a batch, colouring is often used to make them look all the same and distract the eye from a poor one.
Of course, like all tricks of the trade, it’s not just wool that is dyed. Chalk/dyes are used to whiten areas faces and legs that should be pure white in breeds for example.