Native farms are worse than mills (.5f/s vs .67f/s), but cost the same. What’s worse, farms are required to get hunting upgrades past hunting dogs, which means they need to be built much sooner. European civs get steel traps (20% hunting rate) for 125w + 125c, and natives get great feast and harvest ceremony (25% hunting rate) for 725w + 200c.
Tying natural resource collection rate upgrades to long-term collection rate upgrades was originally intended to be a bonus that helps make the transition smooth, and tying farming to livestock was also supposed to be a QoL bonus for natives. Instead, because farms are so expensive, we see the opposite effect. Natural collection rate upgrades are inaccessible, and livestock fattening is inaccessible. These two QoL bonuses are actually penalties, due to design flaws by the original developers (who didn’t get many opportunities to update the game and fix their mistakes).
People rarely build livestock pens for 250w, and they certain won’t ever build a farm (unless it’s free) as a 400w livestock pen. With the logic applied in making farms cost 400w, rice paddies should also cost 600w because they double as an estate. Of course, nobody wants that.
In my opinion, the following changes should be made: Farm wood 400 -> 250, native estate wood 600 -> 400.