[Someone]

Shearing requires advanced technology that the Vikings may not have had. https://www.griggsagri.co.uk/blog/sheep-shearing-a-brief-his...:

“The sheep were shorn using very basic tools, such as metal, or sharp glass, fashioned into an implement to take whole clumps of wool off at once. Over time, the tools were adapted into scissor-like blades to make the job easier.”

I think you can call that plucking. People use tools to pluck grapes, too.

And 100 a day without a powered tool? Is that realistic?

[rags2riches]

These are examples of Viking era shears, found in what is now Sweden. I just did a quick search. Search words: sisare järnålder.

http://samlingarna.gotlandsmuseum.se/index.php/Detail/object...

https://historiska.se/upptack-historien/object/364462-sax-si...