For what it's worth, a chain is a literal standardized metal chain that surveyors used when physically staking out parcels. It's not a unit normal people have ever used.
An acre is a chain by a furlong because a furlong is the distance you'd plow with an ox, and an acre is about the area you'd plow in a day. They derived the standard chain from that, much as metric chains are 20 meters or 30 meters. France used to use 10 meter chains, with 20cm links.
Normal people don't measure things in chains, whether metric chains or imperial.
For what it's worth, a chain is a literal standardized metal chain that surveyors used when physically staking out parcels. It's not a unit normal people have ever used.
An acre is a chain by a furlong because a furlong is the distance you'd plow with an ox, and an acre is about the area you'd plow in a day. They derived the standard chain from that, much as metric chains are 20 meters or 30 meters. France used to use 10 meter chains, with 20cm links.
Normal people don't measure things in chains, whether metric chains or imperial.
But what happens if you have a weak ox or a really fast ox? Then the distance would change, affecting the area, no?
Not really, since plotting land would be based off of the average Ox. That just means you'd be done with that field slightly sooner.
The main issue is, over great distances, the chains will stretch so the measurements will end up varying.