How to Build a Cat Mill (Jenny Mill)
A cat mill, also called a jenny mill, is a backyard exercise machine for dogs: a center post with rotating arms, where the dog is harnessed to one arm and chases a lure on the arm in front of it around a circular track. You can build one from a vehicle rear axle, a rim or steel pipe hub and 2" square tubing arms. Below are our free blueprints, the parts list, how to prepare the track and how to use it safely.
A jenny mill or cat mill is a large piece of exercise equipment providing friction free weight training for dogs.
The jenny mill resembles a miniature version of a horse walker. The dog is harnessed to one of three spokes that projects from a rotating center shaft. A lure is attached to a spoke just in front of the dog. The lure brings out the dog's natural prey drive and entices them to run on the track.
Many years ago, cats were placed in cages as a form of bait. This is how it got the name cat mill. We do not recommend using any form of live bait. A toy, tug or hide lure works just as well and is the only acceptable option.
What are the benefits of using the jenny mill?
The benefits of exercising your dog on the jenny mill include better cardiovascular health, increased muscle build, and improved mental health.
It's an excellent tool for releasing pent up energy. Some of the unwanted behavior that is associated with pent up energy includes chewing on furniture, digging holes in the yard, excessive barking, jumping, and mouthing / play biting.
Hard-working dogs burn through calories fast. A high-calorie performance food helps your dog hold weight and energy through training.
FUEL HARD WORK WITH BULLY MAX PRO SERIES 31/25
High-calorie performance nutrition with 31% protein, 25% fat, and 600 calories per cup for working and sport dogs.
Cat mill vs. slat mill vs. treadmill
| Equipment | How it works | Best for |
|---|---|---|
| Cat mill / jenny mill | Dog runs a circle outdoors, chasing a lure on a rotating arm | Prey-drive dogs, outdoor conditioning, DIY builders |
| Slat mill | Dog-powered belt of slats, no motor | Sprint work and slat mill racing |
| Motorized treadmill | Belt speed set by the handler | Steady walking or trotting, bad weather days (see dog treadmill training) |
How to build a jenny mill / cat mill (Blueprints)
Parts list
- A car or truck rear end / axle for the rotating center shaft. This part can be found at your local junk yard, on Craigslist, or on eBay. We recommend finding a local source to avoid shipping costs.
- A car rim or steel pipe attached to the axle as a base for your spokes (2" square tubing).
- Eye bolts on the ends of each spoke (for the lure, chains, and to attach the cable to the dog's harness).
- A cable with good elasticity to connect the harness, and a well-fitted harness. Never attach the mill to a collar.
Get all of the blueprints on one file
Before the first run, check that every weld and bolt is solid, there are no sharp edges at dog height, and the arms turn freely without wobbling.
How to prepare the ground / track
By taking your time and preparing the track properly, you will avoid injuring your dog's pads.
Remove rocks, sticks, or any hard objects from the track.
Once the track has been cleared, spread hay over the surface. On top of the hay, spread cedar chips.
Preparing the track this way will provide the dog with a soft surface to run on with minimal strain on their joints.
If you want to upgrade to a premium surface, we recommend using rubber mulch as an alternative to the cedar chips.
The benefits of using a rubber mulch surface VS cedar chips:
- Provides a softer surface
- Does not attract termites
- Reduces weed and mold growth
- Provides excellent drainage
Best practices
- Never leave your dog on the jenny mill unattended. Stay right there for the whole session.
- Do not use chains to harness your dog to the jenny mill. Chains can get tangled under the dog's legs and cause injury. Instead, use a cable with good elasticity.
- Warm your dog up with a few minutes of walking first, and skip sessions in hot, humid weather.
- Keep your dog hydrated during exercise and follow up with a quality recovery meal.
- The location of the jenny mill should be in an area with excellent drainage. Ideally, it should be placed on a level surface on the top of a hill.
- By adding the hardware used on a traditional spring pole to the lure, the jenny mill can also act as a spring pole. Keep your dog attached to the jenny mill and give them the lure to pull on.
- After workouts, reward your dog by giving them the lure.
Hard workouts call for a calorie-dense recovery meal. Pro Series 31/25 packs 600 calories per cup for working and sport dogs.
A quick behind-the-scenes slat mill clip from Bully Max Sports:
TRY BULLY MAX PRO SERIES 31/25 DOG FOOD
High-calorie performance nutrition with 31% protein, 25% fat, and 600 calories per cup for working and sport dogs.
Can all breeds use the jenny mill?
Most healthy adult dogs with some prey drive can. As long as your dog shows willingness to play on flirt poles and spring poles, they will likely enjoy using the jenny mill as well. Flat-faced breeds like French and English Bulldogs overheat easily, so keep their sessions short and cool.
What kind of lures can you use?
We recommend using cow hides for the lure. However, you can use just about any toy that your dog shows interest in. Supervise and take the lure away before your dog can tear off and swallow pieces.
To increase your dog’s interest in the lure, try a squeaky toy, a fresh lure your dog hasn’t seen before, and lots of excited verbal encouragement. More ideas are in our flirt pole guide.
How often should you use it?
You can use the jenny mill 2-3 times per week.
Start short and stop while your dog still wants more. Many dogs in good health will run 5-10 minutes at first. Watch for heavy panting, slowing down, stumbling or losing interest, and end the session before your dog is exhausted. Then give them the lure to tug on gently until their breathing returns to normal.
As your dog builds stamina over several weeks, you can gradually increase the length of their workout sessions to 15-20 minutes.
A sturdy tug toy works well as a lure and for a cool-down tug session after the run.
TRY THE BULLY MAX HEAVY-DUTY TUG TOY
A tough linen or jute tug with nylon handles. Built for drive building, training, and interactive play with strong dogs.
How old does my dog need to be in order to use the jenny mill?
The jenny mill should be used on dogs that are fully matured. Using the jenny mill on puppies can lead to injury and can affect their development. The best exercising tool for puppies is the flirt pole, used gently. Not sure how much exercise your dog needs? See how much exercise a pitbull needs.
Conditioning builds muscle only when the diet keeps up. Pair your jenny mill work with Bully Max Pro Series 31/25, high-performance, meat-based nutrition for working and sport dogs.
1 comment
Does anyone still sale the small portable jenny/cat mills any more ?