Quick Summary: Doing the County Math

• Horses Allowed: This is the final number. It is the simple answer everyone wants (e.g., "You can have 4 horses"). However, this number rarely appears explicitly in the zoning code.
• Animal Units (AU): This is the formula counties use to calculate that final number. It measures the "impact" of an animal on the land. Typically, 1 Horse = 1 Animal Unit.
• The "Mix and Match" Benefit: The AU system is flexible. If your zoning allows "4 Animal Units," you are not forced to have just 4 horses. You could usually trade 1 horse for 4 goats or 5 sheep, depending on the specific conversion table.
• The "Open Space" Trap: Some counties (like Jefferson) do not just count acres; they require a specific amount of usable, open land per animal, excluding your house and driveway.

You open the zoning code for a property in Franktown, expecting to see a clear rule like "2 horses per acre." Instead, you find a complex chart referencing "Animal Units," "Gross Acreage," and "Livestock Equivalents."

It feels like you need a degree in algebra just to figure out if you can bring your two geldings and a miniature donkey.

Understanding the difference between "Animal Units" and the final "Horses Allowed" count is critical. If you miscalculate, you could end up buying a property that is legally too small for your herd.

Here is how to decode the zoning math used by Colorado counties.

1. What Is an "Animal Unit" (AU)?

Counties do not want to write a separate rule for every single species of farm animal. Instead, they use a standard unit of measurement called the Animal Unit (AU).

Think of an Animal Unit as a measure of "impact." It accounts for how much an animal eats, how much manure it produces, and how much water it drinks.

• The Gold Standard: In almost every Colorado county, 1 Mature Horse (1,000 lbs) = 1.0 Animal Unit.
• The Cow Equivalent: A mature cow is also typically 1.0 AU.
• The Small Animal Fraction: This is where it gets useful. Smaller animals count as fractions.
• Miniature Horse: Often 0.25 to 0.5 AU (meaning 2 to 4 minis equal 1 big horse).
• Goat/Sheep: Often 0.2 to 0.25 AU (meaning 4 to 5 goats equal 1 big horse).
• Llama/Alpaca: Often 0.25 to 0.5 AU.

2. From "Units" to "Horses Allowed"

To find out how many horses you can have, you have to take the AU limit for your zone and do the math.

• The Scenario: You find a 5-acre property in a zone that allows "1 Animal Unit per acre."
• The Math: 5 acres x 1 AU/acre = 5 Total Animal Units allowed.
• The Result: You can have:
• 5 Horses (5 x 1.0)
• OR 3 Horses and 8 Goats (3 x 1.0 + 8 x 0.25)
• OR 2 Horses, 2 Cows, and 4 Alpacas.

This system gives you the freedom to build a mixed herd without violating the code.

3. The County Variations

Every county defines an "Animal Unit" slightly differently. You cannot assume Douglas County math works in Jefferson County.

• Douglas County: They generally treat 1 Horse, Mule, or Cow as 1 AU. But they treat Swine, Sheep, Goats, and Alpacas as 0.25 AU (4 animals = 1 Unit).
• Jefferson County: Jeffco often uses a "square footage" calculation instead of a flat per-acre rule. In some residential zones, you need 9,000 square feet of open lot area for the first animal and 6,000 square feet for each additional one.
• Elbert County: In agricultural zones, they often do not strict "count" units but instead enforce "health and safety" standards. If the land is overgrazed and dusty, you are in violation, regardless of the number.

4. The "Usable Land" Trap

This is the most common mistake buyers make.

• Gross vs. Net Acreage: Zoning codes often base the calculation on available open space.
• The Example: You buy a 2-acre lot. But after you subtract the house footprint, the driveway, the septic field, and the garage, you only have 1.2 acres of "open space."
• The Consequence: If the code requires 1 acre of open space per horse, you might legally be limited to 1 horse, even though you own 2 acres of land.

We Do the Math For You

You shouldn't have to guess if your miniature donkey counts as half a horse or a quarter of a horse.

When we evaluate a property, we pull the specific zoning table for that exact parcel. We calculate the net usable acreage and give you a hard number: "This property allows 4 horses and 2 goats legally."

Contact Us Today if you are confused by a specific property's zoning.

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Frequently Asked Questions (FAQ) About Animal Units