Published
The numbers that turn a farm into a regulated facility.
The county has a definition, and it is a numbers test
Buying ground near working agriculture around St. Anthony raises a question people find hard to ask politely: how big can the operation next door get, and does the county treat it differently once it does? There is an appendix for that, and it answers with counts rather than adjectives.
A confined animal feeding operation is a facility where all three of the following are true.
- Animals have been, are, or will be stabled or confined and fed or maintained for a total of ninety consecutive days or more in any twelve-month period.
- Crops, vegetation, forage growth or postharvest residues are not sustained in the normal growing season over any portion of the lot or facility.
- The lot or facility is designed to confine, or actually does confine, as many as or more than the numbers in the table below.
All three conditions have to hold together. A pasture that grows forage is not a CAFO however many animals cross it, because the second condition fails. That is the distinction the definition is built around: confinement plus bare ground plus scale.
The thresholds, by animal
| Animals | Number at which the definition can be met |
|---|---|
| Mature dairy cows, whether milked or dry | 700 |
| Veal calves | 1,000 |
| Cattle other than mature dairy cows or veal calves | 1,000 |
| Swine weighing 55 pounds or more | 2,500 |
| Swine weighing less than 55 pounds | 10,000 |
| Horses | 500 |
| Sheep or lambs | 10,000 |
| Chickens | 82,000 |
These are large numbers, and that is the reassuring half of the answer. An ordinary farm with stock on it is nowhere near this definition. The appendix is aimed at industrial-scale confinement, not at a neighbour with cattle.
The appendix also defines an animal unit as one thousand pounds of live weight, which is the unit the rest of its provisions work in.
The area of influence is a mile
Two definitions matter more than the thresholds for anyone buying a house, because they describe geography rather than livestock.
“‘CAFO area of influence’ means: the area within one mile of the CAFO site boundary.”
— Fremont County Development Code, 2011 Edition (Ordinance 2011-04), Appendix W, section 1.02.030. Consolidated through Ordinance 2026-03. Retrieved 1 September 2026
And the CAFO site is a defined area containing the pens, waste storage and lagoons — with the boundary of that area being the point from which setbacks and other distances are measured.
Two practical consequences follow. Distances are measured from the pens and lagoons rather than from the property line of the farm, which usually works in a neighbour's favour. And the area of influence extends a full mile, so a house well outside sight of an operation can still sit inside it.
The appendix also defines confined in a way worth knowing: animals placed in a pen, corral or other facility that restrains or concentrates them such that the vegetative cover is worn down or destroyed beyond its ability to naturally recover in a single season. And it adds a clarification that heads off a common worry — the existence of field or property-line fencing does not automatically create a condition of confinement.
What to establish about anything operating nearby, since each answer changes whether the appendix engages at all:
- Are animals confined for ninety consecutive days or more in any twelve-month period?
- Does any portion of the lot sustain crops, vegetation, forage or postharvest residue during the normal growing season?
- What species, and how many, measured against the published thresholds?
- Where exactly are the pens, waste storage and lagoons, since those define the site boundary?
- How far is the house site from that boundary, measured against the one-mile area of influence?
- Was the facility legally operating before 1 July 2011, which makes it an existing CAFO?
Where the authority comes from, and what that means
Appendix W is unusual among the county's appendices in how much of it is not the county's own. It records that Idaho Code 67-6529 authorises Fremont County to regulate the siting of certain animal operations, and that the provisions of Idaho Code 67-6529A through 67-6529G are incorporated herein and are absolute performance standards.
It then states a conflicts rule: as provided in Idaho Code 67-6529(2), if any provision of the Development Code conflicts with this Appendix, this Appendix shall govern.
Those are the county's own characterisations of the statutes, and the statutes themselves are where the operative law sits — worth reading, or taking advice on, before relying on any of this in a real dispute. What the appendix establishes clearly is the hierarchy: on this subject, Appendix W wins against the rest of the code.
One further definition matters for anything already operating: an existing CAFO is any livestock confinement facility legally operating prior to July 1, 2011. A facility on the ground before that date is in a different category from one proposed today.
What a buyer should actually do
- Ask what is operating within a mile of the parcel, since the area of influence is defined at that radius from the site boundary.
- Find out where the pens, waste storage and lagoons are, because those define the site boundary from which distances are measured — not the farm's property line.
- Ask whether any nearby facility was legally operating before 1 July 2011, which puts it in the existing-CAFO category.
- Check the three-part definition rather than reacting to the sight of livestock. Ground that sustains forage in the growing season fails the second condition regardless of animal numbers.
- Remember the thresholds are large. An operation has to reach genuinely industrial scale before this appendix engages at all.
- Treat this as separate from the right-to-farm question, which is its own subject and is covered by the agricultural nuisance waiver a buyer may be asked to sign, alongside what applies when acreage is inherited rather than bought.
- If a real dispute is in prospect, read Idaho Code 67-6529A through 67-6529G, since the appendix incorporates them as absolute performance standards rather than restating them.
The honest summary for most buyers around St. Anthony is that this appendix will never engage. It is worth ten minutes anyway, because the one thing it establishes cheaply is the difference between a neighbour who farms and a facility the county regulates as an industrial use — and knowing which is next door is the sort of question that is easy to answer before a purchase and awkward to raise afterwards.
Common questions
What counts as a CAFO in Fremont County?
A facility meeting all three conditions: animals confined and fed for ninety consecutive days or more in any twelve-month period; crops or vegetation not sustained in the normal growing season over any portion of the lot; and animal numbers at or above the thresholds the appendix lists.
How many animals does it take?
700 mature dairy cows, 1,000 veal calves, 1,000 other cattle, 2,500 swine at 55 pounds or more, 10,000 swine under 55 pounds, 500 horses, 10,000 sheep or lambs, or 82,000 chickens.
Is a neighbour with livestock a CAFO?
Almost certainly not. All three conditions must hold together, and the thresholds are industrial in scale. Ground that sustains forage during the normal growing season fails the second condition regardless of how many animals are on it.
How far does a CAFO's area of influence reach?
The CAFO area of influence means the area within one mile of the CAFO site boundary. A house well out of sight of an operation can still fall inside that radius.
Where are distances measured from?
From the CAFO site boundary — the defined area containing the pens, waste storage and lagoons. That is the point from which setbacks and other distances are measured, rather than the farm's property line.
Does fencing make land a confinement facility?
No. The appendix states that the existence of field or property-line fencing does not automatically create a condition of confinement. Confinement turns on vegetative cover being worn down beyond natural recovery in a single season.
What is an animal unit?
One thousand pounds of live weight. It is the unit the appendix's other provisions are expressed in.
What is an existing CAFO?
Any livestock confinement facility that was legally operating prior to July 1, 2011. A facility predating that date is treated differently from one proposed now.
Does this appendix override the rest of the code?
On this subject, yes. The appendix records that under Idaho Code 67-6529(2), if any provision of the Development Code conflicts with the appendix, the appendix governs.