I just checked. In my games farms seem to function normally. Crop farms will start to produce at maximum capacity since they are primary resource plants, like coal mines or forests. So all farms will always have a full production bar.

That is it the way the developers have hardcoded the workings of primary resource plants. Many of us would like to have seen production based upon demand, as it was in TpF1. But is was too complicated for many casual players, and it introduced some weird side effects that the developers not seemed to be able to fix. So they chose to have primary industries to always produce at full capacity.

So, no bug, but feature. ;)

Ah, my bad, I conflated an two observations.

The specific problem I'm observing is that when I introduce a second farm into my supply chain, it produces at a very slow rate. Eg, after 5 months it produced only a few (3-4) cattle.

It is producing (ie, I verified that it is connected), but very slowly. The first farm produces fine.

Have you observed this? I don't have any mods that I think would conflict.