I don't go by number, I go by main purpose of the farm. If the farm's main purpose is to produce nicely conformed, well bred horses then I consider it a breeding farm. Even if they only produce 5 foals a year, if those foals are top quality then they are a breeding farm to me.

A farm that breeds but also gives lessons or something is not a breeding farm to me.

A BYB'er with 20 mares and a single stud doesn't count as a breeding farm to me.
A place that gives lessons as well as breeds doesn't count as a breeding farm to me.

i wouldn't base it off quantity, but quality of horses if there 1 nice stud and 3 nice mares and they can produce a 30,000 dollar colt. thats a breeding farm to me, not to mention most studs also have mares brought to them, theres no telling how many of those pay just to get theres bred

ex. holistiner breeding farm: 3 stallions/6 mares very fancy!

ex. all horses (maninly jumper) 11mares/8? stallions Nice!

ex. 14 mares/2 stallions (all horses) GOOD

i would have to say the lowest should be 3 stallions and 6 mares, thats not very many horses, but with awsome bloodlines

I would not consider a farm to be a breeding farm unless it was operated by professionals with a goal of making a profit. There are many "hobby" operations where someone keeps a few mares and maybe a stallion.

FWIW, not all commercial breeding operations have both mares and stallions. Some Thoroughbred breeding operations operate as "stallion stations," standing as many as 40 stallions (Gainesway farm in Lexington, at its heyday) to outside mares, and some commercial breeding operations do not stand any stallions at stud, preferring instead to own shares in/book their mares to stallions that stand at other farms, rather than going through the expense of building facilities for stallions and managing and promoting stallions.

There are some breeders who don't own a farm at all. The Phipps family, for instance, breeders of horses like Bold Ruler, Personal Ensign, and many other champions, board all their mares and stallions at Claiborne Farm, which manages the broodmare band and stallions for the Phipps family.

There are some farms in Kentucky that operate purely as boarding operations for broodmares. They may not own a single horse that's on their property, except for a teaser stallion or two, but they may board dozens of mares and foals and manage them for many different owners.

And of course for breeds that allow the use of frozen or transported semen, you can have an artificial insemination station that does semen collections off-premises, but prepares, stores and ships the semen. A breeding operation without live horses on the premises, if you will.

With embryo transplant from frozen embryos, there's a whole brave new world of commercial breeding operations to consider, too.

I don't think its as much a matter of how horses they have as a matter of what their breeding program is trying to accomplish. It could be as little as 3 mares and 1 stud.

Just purchased my AQHA gelding who is my Congress hopeful and I consider the breeders to have an excellent program…she has 3 mares….breeds to top performance stallions..So In my book its not size that matters its their vision and breeding program and what they produce…quality