Animals that are assigned to pens cannot pass through fences or barricades. Build fences to enclose pens and prevent your animals from escaping.Pen markers have an “auto cut” option which will periodically designate inedible plants in the pen to be cut. Once placed, you can assign a certain set of animals to the pen and handlers will bring the correct animals over. Pen marker: Build a pen by placing a pen marker in an enclosed room or fenced off area.
RimWorld 1.3 patch notes New stuff: Base game Pens and animals Today’s RimWorld patch 1.3 will fix a few of these issues.
