The following issues were inherited from the original AOE3 game.
It’s easy to re-create these issues.
Settlers who gather food at the livestock will not move on to a different fattened livestock animal, and simply stop gathering (e.g. when there are no fattened cows left but there are fattened sheep near by).
When settlers are done gathering food from all fattened livestock they go idle, and do not resume their gathering when new fattened livestock are released.
These settlers should resume such gathering automatically just like they do so when new shipments of resources are available near the TC.
Settlers line of site for livestock is very low to a point where they would not move on to fattened livestock on the other side of the livestock building.
Therefore, these settlers will go idle despite the fact there are more fattened livestock available.