Aivituvin AIR31 against the Formex Snap Lock
A fir coop that claims nothing against a plastic one that claims too much. Both are small; only one of them is honest about it, and it is not the one you would expect.
We have not handled these coops, and we do not pretend to have. Here is what we did instead. Links to Amazon earn us a commission at no extra cost to you - disclosure.
| # | Coop | Best for | Honest count | Price |
|---|---|---|---|---|
| 1 |  Hatching Time Formex Snap Lock Large Chicken CoopTop pickThe one coop here whose material genuinely earns its price, sized for four hens rather than the six on the box. | Cleaning, and cold that stays out | 4box says 6 | Check price#ad |
| 2 |  Aivituvin AIR31 Wooden Hen HouseWell made for the money and unusually honest by omission - Aivituvin publishes no bird count here at all. | A tidy two-hen setup in a small yard | 3no claim made | Check price#ad |
These two coops are close in price and size, and they represent the two material philosophies at the small end of this category. Comparing them is a useful way to see what actually separates a good small coop from a mediocre one.
The numbers, side by side
| Formex Snap Lock Large | Aivituvin AIR31 | |
|---|---|---|
| Published size | 64"L x 39"W x 42"H | 74.9"L x 26"W x 39.4"H |
| Material | Double-walled polyethylene | Fir |
| Floor area | 17.3 sq ft | 13.5 sq ft |
| What that area covers | Enclosed henhouse only | Whole unit including the run beneath |
| Maker's bird claim | 4 to 6 hens | None stated |
| Honest count | 4 hens | 3 hens on a generous reading |
The critical row is the third from the bottom. The Formex's 17.3 square feet is all enclosed floor - it is a standalone henhouse with no run attached, so what you measure is what the birds roost on. The Aivituvin's 13.5 square feet spans the open run underneath the raised house, so its actual roosting floor is a fraction of that.
Compared like for like, the gap is much wider than the raw figures suggest. The Formex has meaningfully more usable coop.
Where the Aivituvin wins
It claims nothing. Aivituvin publishes no bird count for the AIR31, which in a category where the typical claim is double the arithmetic is genuinely creditable. There is nothing on that listing for us to correct.
It is also cheaper, comes with a run already attached, and the pull-out tray and ramp are better executed than most fir coops at the price.
Where the Formex wins
The material, and it is not close. Double-walled polyethylene does not rot, does not absorb moisture, gives red mite nowhere to colonize in its seams, and hoses out in minutes. Fir does the opposite on all four counts, and mite living in the joints of a wooden coop is one of the most common reasons people give up keeping chickens.
It also has more enclosed floor, and its panels unclip without tools, which is the difference between a coop that gets deep-cleaned twice a year and one that does not.
Which to buy
The Formex Snap Lock Large, for four hens, if the budget stretches. You are paying for a material that will still be serviceable when the fir coop needs replacing, and for the cleaning access that decides whether a coop stays healthy.
The Aivituvin if you want a coop and run in one purchase at a lower price, and you are keeping two or three birds. It is a decent object honestly marketed; it is just small.
Top pick · Cleaning, and cold that stays out
Hatching Time Formex Snap Lock Large Chicken Coop
The one coop here whose material genuinely earns its price, sized for four hens rather than the six on the box.
What the numbers say
64in x 39in = 17.3 sq ft of enclosed henhouse floor. At 4 sq ft per standard hen that is 4 birds, against a claim of 6.
Figures from Hatching Time published specifications (Amazon listing) · 64"L x 39"W x 42"H · Double-walled polyethylene
This is a standalone henhouse with no attached run, so the published footprint is all enclosed floor. That makes it one of the few coops on this site where the generous reading and the honest reading are the same number.
17.3 sq ft supports four standard hens at the 4 sq ft figure. The listing says four to six. Four is right; six is a winter of pecked backs.
Double-walled polyethylene is the reason to buy it. There is no end grain to rot, no seam for mites to colonize, and it hoses out in minutes - the single biggest practical difference between a coop you keep clean and one you avoid.
Good
- Whole footprint is enclosed floor, not run
- Double-walled plastic will not rot, absorb, or harbor mites the way fir does
- Panels unclip for cleaning without tools
Not so good
- Costs more than the wooden coops it outlasts
- No run included, so budget for one
- Plastic walls hold no insulation value on their own
Skip this if: you want a coop and run in one purchase. This is a henhouse only, and pairing it with a run pushes the total past most wooden coop-plus-run kits.
Pick 2 · A tidy two-hen setup in a small yard
Aivituvin AIR31 Wooden Hen House
Well made for the money and unusually honest by omission - Aivituvin publishes no bird count here at all.
What the numbers say
74.9in x 26in = 13.5 sq ft of whole-unit footprint, which includes the attached run and is therefore generous. At 4 sq ft per standard hen that is 3 birds. The maker publishes no bird count of its own to compare against.
Figures from Aivituvin published specifications (Amazon listing) · 74.9"L x 26"W x 39.4"H · Fir
13.5 sq ft across the whole unit, and that figure includes the open run beneath the raised house. The enclosed portion is a fraction of it.
Aivituvin does not claim a bird count for this model. That is worth noting in a category where almost every competitor prints one it cannot support - there is nothing here to correct.
Treat it as a two-hen coop and it is a good one. The pull-out tray and the ramp are better executed than on most fir coops at this size.
Good
- No inflated bird-count claim to correct
- Pull-out tray makes weekly cleaning quick
- Fir construction is solid for the price
Not so good
- Narrow 26in depth limits usable roost space
- Whole-unit footprint counts the run, not just the house
- Fir needs re-treating every couple of seasons
Skip this if: you have three or more standard hens. The depth is the constraint, and no amount of length fixes a 26in-wide house.
- Coops for 4 chickens - the size class both of these sit in
- Metal against wooden coops - the wider material argument
- Full review: Formex Snap Lock Large
- Full review: Aivituvin AIR31
Questions people actually ask
+Is the Formex Snap Lock coop worth the price?
+How many chickens does the Formex Snap Lock Large hold?
+How many chickens does the Aivituvin AIR31 hold?
+Is a plastic chicken coop better than a wooden one?
+Do Aivituvin coops come with a run?
Sources
Read next
Formex Snap Lock Large Chicken Coop
17.3 sq ft of real henhouse floor in double-walled polyethylene - four hens, not the six on the box.
Aivituvin AIR31 Wooden Hen House
13.5 sq ft whole-unit, no claimed bird count, and a 26in depth that decides everything. A good two-hen coop.
Chicken coops for 4 chickens
Four hens need 16 sq ft. The coops whose published dimensions genuinely reach it, ranked.
Metal against wooden chicken coops
Metal wins for runs, wood for henhouses - and most metal 'coops' are really runs with no house.
The best chicken coops, ranked by what they actually hold
The flagship roundup. Twelve coops ranked on measured floor area against the maker's own bird-count claim.
Plastic against wood, in the cold
A material comparison judged on condensation, cleaning and mite resistance rather than on an insulation value neither material really has.