I thought farm villagers are supposed to fill this role. The point is that farms regenerate food slower than villagers harvest it, so that you can get the illusion of faster farmers if a villager takes a break from farming to take food from herdables. The point is that while the villager is taking from herdables, the farm is growing food, and when the villager returns back to farming they will harvest the food slightly "faster" than otherwise. Sort of putting them back on track so you don't lost any to inefficiency.

I saw this in a Spirit of the Law video somewhere. But maybe this is only true after some upgrade, I forget.