Multi-species rotational grazing on my farm.
In the discussion about TLC Ranch eggs / honestmeat.com closing its doors, I made a comment about the amount of space required to pasture hens. the context was "why do they need 48 acres of land (and the related expenses of that land) for just 2,000 hens?
Here's my entire comment:
"Rebecca states in her interview that she had 2,000 laying hens at the end.
Giving each hen a 1/2 square foot of grass per day that's 1,000 square feet a day. An acre is 43600 square feet, which means that each acre gives you 43 days of rotation for all 2,000 hens. So I'll revise my estimate of land needs for the hens to 3 acres giving a 4 month rest after grazing"
Kelsey, a reader on my blog, reads that and makes this comment [edited for length, but you can read the whole thing in the comments section of that other post]:
"... know that 1/2 square foot per chicken is unacceptable. For comparison - taking into account a healthy adult male's height and weight - imagine living your entire life in a 25 square foot room with 10 or 15 other people. Imagine eating, sleeping, breathing, defecating, establishing social orders and relationships (yes, chickens do that), with less than 3 square feet of space in which to position yourself. Imagine the toll it would take on your mental and physical health."
What I said, and what I meant, was to provide each chicken with 1/2 square foot of NEW GRASS per day, but that is not the entire size of the chicken pen. Land is one of your biggest expenses, and in general, anything you can do to use your land more efficiently (to reduce your land expense if nothing else) is good, in my opinion. So you can allow the chickens any amount of trailing space you want, depending on how much vegetation you have and what your soil conditions are.
The basic concept is Managed Intensive Grazing. The goal is to completely consume the forage on the exposed part. Tasty vegetation is eaten. Not so tasty vegetation is shredded and trampled -- weed control. manure is deposited, and a long regrowth period is allowed to restore the vegetation for the next cycle.
The amount of exposure, the amount of time for regrowth, the number of animals (stocking level) and the amount of manure that can be tolerated will all vary by location.
So in this case you're exposing fresh, new pasture every day, and rotating out consumed, fertilized, weeded pasture. By maintaining the pen you can efficiently use all of your land and precisely control how often it is grazed -- for parasite control, for instance. You can use more land if you'd like, or less. In this particular case I was optimizing for the least amount of land because that was one of the primary complaints related to the closure of this farm -- land cost.
So I'll stand by my basic math: 3 acres for 2,000 hens would do it if you're on a good pasture. Heck, lets double that -- 6 acres!
I wish I could say that I came up with this; I didn't. It's done with chicken tractors, popularized by Joel Salatin, and most recently I found a video of a farm operation in Canada that is both profitable and pasture based, which you'll find here. Special thanks to Kevin Kossowan for his video series "From Local farms".