The idea here would be basically the same "farm animals" look at the terrain bellow if the fodder was out, the animal eats the terrain.
But the start of the idea would be-
All or some Terrains eatable for animals
- ^~
Animal Q for eating terrain
-This would have no impact on the animals Q of feed. (This is an important part, Q terrain should not effect animals. this is for nomads)
+++++To avoid exploiting (by townsmen) plant grass should always be planted as "cut grass".
Growing periods terrain
-if the terrain = grassy(or few others) terrain. the animals would eat it.
-But instead of being stomp to dirt. the grass would turn slightly darker to indicate "cut grass" and this spot would no longer produce food until grown back.
-Grass should grow back the fastest of the terrains (3-4 days).
-Other terrains that could be suitable for feed would also do the same (being cut/darken) and grow back in (7-14 days)
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The idea of all this adds into a Nomadic life style for those that travel around with a horse (and hopefully others types later).
but are't able to keep up with filling the fodder & being able to breed abit.
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This idea also brings more life to the hearth lands. being able to see where living things have been roaming, as horses will likely eat random terrain while they're out and about.