Did Boeing really use ferrets to run wires through aircraft during construction? I've seen many articles on the internet (here, here &amp; here) claiming that Boeing used a team of ferrets to run cables through hard to reach areas when building aeroplanes, but I've never seen any official sources to back these claims.

Is there any truth to this, or are they just baseless internet rumours?
No, Boeing didn't do that.
I asked their assembly plant tour
to confirm or deny this, when I found
a report that around 2010 some visitors heard this from a tour guide.  On 2020 Nov 3 they replied:

Hello,
Thank you for contacting us with your inquiry. This is a popular urban myth, there are no records or any other evidence that this was done at Boeing.
Thank you again for your interest.