- you do not have to endlessly click on each animal to check the quality since the pen's board will show the list of the animals inside with their qualities and etc.;
- you can take out of the pen the animals that you want to butcher more easily. It is a great pain to butcher them if you do it once a week since they tend to cluster around the exit gates or attempt to wander outside of the fence;
- you can have separate fences for different animal specifications, meaty vs milky cows, milky vs wooly vs meaty sheep, high stamina vs high metabolism or whatever horses and etc.
Let's say I have 20 cows and 1 bull in the pen. In 2 weeks they will be 20 more calfs to check + check the old cows and kill the unneeded ones, that is total of 40 animals. This might take 1+ hour of my time unnecessarily, especially with them tending to cluster and blocking the movement. Most people tend to check even more frequently. So the actual time you would spend on the animal care/selection is several hours, taking 5-8% of your online time (if you're playing for 4 hours a day). I won't bother with selecting specific qualities (wool, meat, milk) and focus on the general average quality. If I would do so, I would spend even more hours on it.
