If only our canine companions understood our language, we could explain the really good reasons for their staying in the yard. However, since interspecies conversation is generally an exercise in futility, Romeo will never understand why exploring the neighborhood on his own is not advisable -- so a pen is necessary.
Considerations of Design
Dogs are ingenious when it comes to escape, so a good pen design must take that into consideration. If your dog is a jumper, digger or exceptional picker of locks, he will get out of a poorly designed pen sooner or later. Plan walls at least 6 feet high and stretched tightly to prevent jumping or climbing. With large dogs, you'll need a fenced roof as well. Extend the walls at least a foot underground or add a concrete strip extending inside the pen a foot or so at the base of the fence all the way around to discourage digging. Avoid solid concrete floors, as they are hard, hot in summer and cold in winter -- and may harm your dog's feet. Choose a human-size gate with a sturdy lock that your dog cannot push, pull or otherwise manipulate to open, and ensure that the gate is snug top and bottom so it will not allow the dog to squeeze through.
Consideration of Materials
Chain-link fence makes the best material for large dog pens as it is strong and durable, and provides for ventilation and visibility as well as security. You can purchase premade panels and erect a pen using poles, clamps and gates designed for chain-link fences, or buy a roll of fencing and make your own panels with pipe or wood frames. Smaller dogs may need only welded wire fencing, but look for galvanized or coated wire for the longest-lasting fence. You will need a shade cloth or a permanent trellis to keep off sun, and a solid, well-built and insulated dog house on a raised platform to protect your dog from weather extremes.
Creating Safe Shelter
You are the guardian of your dog's health and well-being. It is your responsibility to ensure that the pen is safe for her to stay in at all times of the day or night. Put an unbreakable lock on the pen when you are not home – pet theft is a very real danger in some areas. Leave plenty of food for the day. Place clean, fresh water in the pen and put it in a large-capacity spill-proof container, so she does not accidentally spill it or go thirsty if you come home late and she runs out. Give her a comfortable place to get out of the sun and rain; and put in a few dog-safe, age-appropriate toys to keep her entertained. Above all, leave a phone number through which you can be reached – and a spare key to the pen – with a trusted neighbor in case of an emergency.
A Temporary Home Only
Remember that a dog is not a thing to be locked up and forgotten. He needs an inside home and interaction with his family. For his own protection, for safe exercise and fresh air, an outside dog pen may be necessary, but it should never be more than a temporary space for him while you are unable to supervise him closely. Dogs are pack animals, and you are your dog's pack. Putting him in a pen all the time will deprive him of his pack and leave him lonely and stressed. If you have no time in your life for companionship with your canine friend, a dog pen is not the answer. Consider not keeping a dog until your life can more fully accommodate the emotional needs, as well as the physical needs, of a pet.