Using Posts, Bridles, and Collars
Placing Posts
Posts are fence-like blocks for pens and tie points. The available posts are Oak Post, Spruce Post, Birch Post, Jungle Post, Acacia Post, and Dark Oak Post. Place them in a line to form a barrier or use single posts as markers around a pen. They match the wood type in their name, so pick the one that fits your build.
Equipping Animals
Use a Leather Bridle or Cloth Bridle on an animal to lead it. Use a Collar or Bell Collar to mark a tamed animal so you can tell individuals apart. A Saddle is used on rideable animals. Keep bridles and collars in your inventory when moving animals between pens.
Organizing a Pen
Combine posts with a gate and a Chicken Nest for hens. Add an Unbound Hay Block as feed for cows and sheep. Put a Bucket of Axolotl in an aquatic area if you keep axolotls, and use Turtle Egg blocks where turtles nest. Mark your best breeders with a Bell Collar so you can find them quickly when it is time to pair them again.