Hi,
I'd like to suggest something I hope is simply just a matter of turning off pet passable (like with doors) for floor grate or floor bars.
On farms you'll see metal bars are placed on the ground spaced an inch or two apart so that the cattle can't walk across it. One can have a driveway and leave the gate open with these cattle grates and because they can't get a solid footing with their hooves they won't walk across it. Perhaps this could only affect creatures with hooved feet though I suspect it'd be simpler to just make it not pet passable.
Wondering if we could have floor grate or floor bars act in the same way. I'd like to be able to make a cattle pen so my cattle can breed and wander happily but still allow a dwarf in to the area for milking, butchering or what have you. Currently one can use a door but I find the pets all escape as soon as a dwarf opens the door to enter or leave the pen.
Which brings about the second point.. the animals once I've locked them in a pen all sit at the door with blue question marks popping up over them. Though this might be more challenging I'm not sure but it'd be cool if the cattle once it figured out it had no path out resigned itself to wandering around wherever it can go.
Thanks for the great game, really enjoying what you've created.