Priefert or Behlen Magnum (if you can find used as the new ones are lighter weight and no longer powder coated), kennels are a good choice for outdoor cages. The 10 foot panels enable you to design any size cage you choose and enable easy expansion if you desire more space as your monkey matures or you add other monkeys to your troop. These heavy duty panels are powder coated which gives many years of use even outdoors. The panels are also of a size that can be moved if you relocate or just want to change the location of your cage. You can either get extra panels for the top or use horse panels.
Chain link panels are another good choice. They require no maintenance and offer the same benefits of design and size as the Priefert and Magnum cages. Do not use the flimsy chain link widely available as dog kennels today. Monkeys require a heavier gauge wire with a good frame for support.
Custom welded cages are a good choice as well. You can make the cage any size or shape you want. I would suggest having your welder make panels so the cage can be moved easier if you ever need to move it. The panels can be bolted together. I would also recommend you have those panels powder coated. Annual repainting will be necessary on the frames if you don’t to prevent rust.
Height of outdoor cages can add additional space for your monkey. The pros is more space, enticing to climb, simulating the canopy of the rainforest etc. The downside is it is farther to fall with potential for great injury or death, and if you have a monkey that doesn’t want to come down catching them may be next to impossible.
Every outside cage should have a safety double door entry. A double entry prevents accidental escapes and serves as a double locking system. You might miss clicking one lock but odds are you aren’t going to miss 2 on the same day. A double entry needs to only be large enough for you to step inside, lock the door, then unlock the interior door to retrieve your monkey. The unit is generally made of the same material as your enclosure and can be on the outside of the enclosure or set into the enclosure.
Water: Fresh water must be available at all times. You can install a water system from your outdoor faucet with lixits at the end, attach a water bottle which you must refill every day. Most monkeys will not leave a water bottle alone unless it is inserted into a PVC water bottle holder (available from several monkey owners who make them), or a clear water bottle with a lixit attached (also made by several monkey owners).
Food receptacles: Stainless steel bowls are a good choice for food receptacles as they don’t rust. PVC caps attached with dryer hose clamps work well too and a hole drilled in the bottom makes spray washing a breeze.
Catch cages: You may want to add a small catch cage with a guillotine door to any cage where monkeys you do not handle are kept. This could prove invaluable if you need to catch and contain a monkey to take it to the vet or if an emergency evacuation becomes necessary. This can be set up at one end of your enclosure or improvised through a tunnel so the monkey can be caught between the enclosure and the indoor cage. If using the attached catch cage you need to practice training the monkey to enter the cage for a reward or feed treats there so he is accustomed to entering the small area.
Heat sources: Monkeys kept outdoors year round will require a heat/nest box or a heated building. Both can have a heavy duty flap similar to doggie door flaps to help hold the heat inside. A small insulated building can serve the purpose as long as you make sure the heater is out of reach of hands and tails by placing the heater in the human walk in area needed for access to clean. A small mesh wire cage can surround the heater to prevent anything landing on it if the monkey throws anything.
Cooling Sources: If you live in an area with extreme heat in the summer months you may want to add an air conditioner to the building so your monkey can come in and cool off in the hottest part of the day. Another option for cooling is to install an automatic misting system over one end of the outdoor enclosure. Your monkey needs to be able to have an area where the water doesn’t hit too.