It's law, at least here in the USA.
If you got the idea I was putting you down that wasn't my intent.
Awnlee started out with the following sentence with the apparent intent of obtaining feedback on which verb was correct and why.
'The only livestock that could survive in that environment was/were chickens.'
This was basically a literary discussion.
You pointed out that according to the Congressional Federal Record, chicken aren't livestock citing 780-120 and 780-328.
Then Switch Blade said Awnlee had to rewrite the entire sentence because of what you said.
I disagreed and I started my reply off by saying:
Why? Do we always have to go with a definition defined by the law?
I also pointed out to SB that 120 and 328 do not mention poultry, and I mentioned that other countries aren't bound by US Law. Remember Awnlee lives in England not the US.
Since we were discussing literary issues, not legal definitions, I said and quoted a definition from the Cambridge dictionary because it specifically lists chickens as livestock:
Furthermore, dictionaries provide non-legal definitions that are valid for general use. For writing, I will go with definitions that apply to general use. For example:
Animals and birds that are kept on a farm, such as cows, sheep, or chickens
A facetious conversation ensued and I made the above comment, which you highlighted, but forgot to add a smiley.
Bottom line, in a literary situation, I will go with the definition(s) that most people use. The law can constrain the definition to mean a specific thing for a specific reasons, but I really don't care if the literary definition is the more appropriate one to use in a story.