This is a long post, so I'm editing, and adding to, it as the day allows me to, so this post will get longer as the day progresses.
So I built the Heavy Flying Fortress Chicken Tractor. It's way over built and has a few hard to come by materials, it's built to outlive me, but that's not most people's goal.
It is a good design though, and it would be worth the effort to streamline its design. The Light Flying Fortress would still be the same shape and size, just less expensive lumber, less lumber, less hardware (hardwares expensive), easier and simpler framing (which even on the Heavy Flying Fortress was simple to do). Since the Light doesn't exist yet, here's photos of the Heavy, you wouldn't notice the difference between the two, just casually looking at them anyway, so these photos still give you a good idea.
The north side of the tractor. The only side that's solid framed, all other sides are open, or have the roof membrane over them. Construction of this tractor is super easy.
The south side of the tractor is always open, even in winter. That guarantees super ventilation, even in winter. In winter, it's the only open side, the other three sides are closed off with a clear plastic roofing panel.
Blocking three of the four sides, creates an air cushion in the tractor, making the air in the tractor very still, so no drafts, but at the same time, it provides great ventilation. It also floods the entire tractor, front to back, with warming sunshine.
We had a two week cold snap this winter, and got all the way down to minus 5 degrees. Because of this design, like Dr Woods recommended, my flock of thirteen had zero issues with the prolonged cold.
On the new Light Flying Fortress, my idea would be to eliminate the hanging items, the hardware is expensive. Fix mount everything, dust box to the far left, elevated with the roosting bar. Feeder and waterer go to the lower right wall, mounted on wood, sitting on the scaffold bracing.
Those modifications save money and time, in addition now the center of the tractor is completely open, really great for the birds flying up and down from the long roosting bar running down the whole left side.
Another framing simplification is eliminating the main center beam, saving money, but even better, now all people activity will be concentrated along the center of the tractor, where without the center beam, even tall people, will have good head clearance.
This is possible because the Fortress has a belt frame, think of a belt around your waist. Most hoop tractors don't.
It's the wood band you see in the photos that's above the open wire on the sides of the tractor, it completely encircles the tractor in its middle, hence belt frame.
I believe the belt frame ties the tractor together, similar to the way a main center beam does, allowing the main center beam to be eliminated.
The belt frame is important because it keeps the first 27 inches of the sidewalls of the tractor vertical and allows 15 inches of open wire on both of the long sides (the east and west sides). So if you're the height of a chicken, when you stand in the middle of the tractor, as you turn around every side is completely open to your view, the north end has an open wire door.
The belt frame also creates the solid framing space to insert a clear plastic roofing panel in that space, to block wind, but not sunlight in the winter. In addition the belt frame gives you solid framing to easily attach the roof membrane to, where if you use a white PVC 60 mil roofing sheet, will probably last 30 years. If funds are tight you could also use a white or silver tarp, that's not nearly as durable of course.
Another improvement in the framing plan is to move the scaffold bracing you see in the photo, where two braces come together in the center of the doorway. Those braces will be separated, one will attach on the far left of the doorway, the other on the far right of the doorway. Now entering and exiting the tractor is much easier, and less chance of tripping, because the braces are no longer in your path as you walk through the tractor, they're off to each side. They're still doing their job of bracing, and preventing racking, but now they're safely out of the your walking path.
I suggest keeping the the roosting bar along the left, but instead of deck board over a 2x6, use just a turned short side up 2x6, sanded smooth and rounded a little at the top, less expensive, easier to frame, and no poop on the board.
Perhaps tie the dust box frame, into the roosting bar framing, close to the far end (in photo), which is the south end of the tractor.
I do want to keep the basic size of 8 feet (really 99 inches) by 16 feet feet for the core of the tractor, where the chickens live.
The reason I think it's important to keep the size at roughly 8x16 is that easily accommodates the 12 hens and one rooster I have, giving each about 10 square feet of floor area. It costs very little more to make this size, and with all the trouble, hardware and such, if you go smaller, you'd have a tractor that couldn't really house many birds at all. This is a pretty serious undertaking in time and money, might as well do it right.
Also the shape and size works well with Dr Woods principles on open air, and ventilation. This tractor always faces South with completely open wire side, and the other three sides are open too, but they're closed with a clear plastic roof panel in the winter.
You'll never have inadequate ventilation using this setup, and as a tractor, poop management consists of taking five minutes to pull your tractor once a week with a chain draped over your vehicle's trailer hitch.
If you free range everyday like me, even more chickens could be housed. It would also be very easy to use a cheap tractor, with zero amenities (ala Joel Salinger, Google him), to double the daytime foraging area.
Just use 48 inch hardware cloth, rolled the long way and zip tied, to connect them, certainly they'd want to roost in the Fortress, so just slide a pop door to close off the cheap companion tractor at night.
Back to the Light Flying Fortress, first we drop down from salt water pier lumber of rough cut 2x6's, and instead go with all regular pressure treated lumber (ground contact), commonly available at places like Home Depot. I don't think it's a good idea to use untreated wood on something like a tractor, that's always exposed to weather. I also read an article by an expert, who says exposed treated wood will last a lot longer if an annual water repellant is applied, something like Thompsons Water Seal.
The skid system and the main bottom frame would both be constructed from regular ground contact pressure treated 2x8's from Home Depot, that's easier and less expensive than rough cut lumber.
Initial construction of the skid and lower frame, is best done by elevating the frame and skid systems, to make them easier to work on, we used 5 gallon buckets in this photo. I would build the skid system, and attach the main frame to it, before adding any super structure to the tractor.
It's incredibly convenient, being able to lift and flip the frame and skid system at will. With a little help from others, it's easy to do.
An easy way to make sure the frame is square, you must do that before attaching the scaffold bracing, which locks it in, is to make sure the diagonal measurement between both sets of corners is same. If the frame is level, and both diagonal measurements are the same, you know the frame is square, that's important.
Here's the Heavy Flying Fortress frame being constructed. You can tell the frame is right side up because the upper level scaffold braces, which are covered in white PVC pipe, are on top.
The PVC pipe will be wrapped in Gorilla Tape (duct tape on steroids), it's worth doing, the chickens love to perch on the pipe and look out through all the open wire, on all sides of the tractor.
So I built the Heavy Flying Fortress Chicken Tractor. It's way over built and has a few hard to come by materials, it's built to outlive me, but that's not most people's goal.
It is a good design though, and it would be worth the effort to streamline its design. The Light Flying Fortress would still be the same shape and size, just less expensive lumber, less lumber, less hardware (hardwares expensive), easier and simpler framing (which even on the Heavy Flying Fortress was simple to do). Since the Light doesn't exist yet, here's photos of the Heavy, you wouldn't notice the difference between the two, just casually looking at them anyway, so these photos still give you a good idea.
The north side of the tractor. The only side that's solid framed, all other sides are open, or have the roof membrane over them. Construction of this tractor is super easy.
The south side of the tractor is always open, even in winter. That guarantees super ventilation, even in winter. In winter, it's the only open side, the other three sides are closed off with a clear plastic roofing panel.
Blocking three of the four sides, creates an air cushion in the tractor, making the air in the tractor very still, so no drafts, but at the same time, it provides great ventilation. It also floods the entire tractor, front to back, with warming sunshine.
We had a two week cold snap this winter, and got all the way down to minus 5 degrees. Because of this design, like Dr Woods recommended, my flock of thirteen had zero issues with the prolonged cold.
On the new Light Flying Fortress, my idea would be to eliminate the hanging items, the hardware is expensive. Fix mount everything, dust box to the far left, elevated with the roosting bar. Feeder and waterer go to the lower right wall, mounted on wood, sitting on the scaffold bracing.
Those modifications save money and time, in addition now the center of the tractor is completely open, really great for the birds flying up and down from the long roosting bar running down the whole left side.
Another framing simplification is eliminating the main center beam, saving money, but even better, now all people activity will be concentrated along the center of the tractor, where without the center beam, even tall people, will have good head clearance.
This is possible because the Fortress has a belt frame, think of a belt around your waist. Most hoop tractors don't.
It's the wood band you see in the photos that's above the open wire on the sides of the tractor, it completely encircles the tractor in its middle, hence belt frame.
I believe the belt frame ties the tractor together, similar to the way a main center beam does, allowing the main center beam to be eliminated.
The belt frame is important because it keeps the first 27 inches of the sidewalls of the tractor vertical and allows 15 inches of open wire on both of the long sides (the east and west sides). So if you're the height of a chicken, when you stand in the middle of the tractor, as you turn around every side is completely open to your view, the north end has an open wire door.
The belt frame also creates the solid framing space to insert a clear plastic roofing panel in that space, to block wind, but not sunlight in the winter. In addition the belt frame gives you solid framing to easily attach the roof membrane to, where if you use a white PVC 60 mil roofing sheet, will probably last 30 years. If funds are tight you could also use a white or silver tarp, that's not nearly as durable of course.
Another improvement in the framing plan is to move the scaffold bracing you see in the photo, where two braces come together in the center of the doorway. Those braces will be separated, one will attach on the far left of the doorway, the other on the far right of the doorway. Now entering and exiting the tractor is much easier, and less chance of tripping, because the braces are no longer in your path as you walk through the tractor, they're off to each side. They're still doing their job of bracing, and preventing racking, but now they're safely out of the your walking path.
I suggest keeping the the roosting bar along the left, but instead of deck board over a 2x6, use just a turned short side up 2x6, sanded smooth and rounded a little at the top, less expensive, easier to frame, and no poop on the board.
Perhaps tie the dust box frame, into the roosting bar framing, close to the far end (in photo), which is the south end of the tractor.
I do want to keep the basic size of 8 feet (really 99 inches) by 16 feet feet for the core of the tractor, where the chickens live.
The reason I think it's important to keep the size at roughly 8x16 is that easily accommodates the 12 hens and one rooster I have, giving each about 10 square feet of floor area. It costs very little more to make this size, and with all the trouble, hardware and such, if you go smaller, you'd have a tractor that couldn't really house many birds at all. This is a pretty serious undertaking in time and money, might as well do it right.
Also the shape and size works well with Dr Woods principles on open air, and ventilation. This tractor always faces South with completely open wire side, and the other three sides are open too, but they're closed with a clear plastic roof panel in the winter.
You'll never have inadequate ventilation using this setup, and as a tractor, poop management consists of taking five minutes to pull your tractor once a week with a chain draped over your vehicle's trailer hitch.
If you free range everyday like me, even more chickens could be housed. It would also be very easy to use a cheap tractor, with zero amenities (ala Joel Salinger, Google him), to double the daytime foraging area.
Just use 48 inch hardware cloth, rolled the long way and zip tied, to connect them, certainly they'd want to roost in the Fortress, so just slide a pop door to close off the cheap companion tractor at night.
Back to the Light Flying Fortress, first we drop down from salt water pier lumber of rough cut 2x6's, and instead go with all regular pressure treated lumber (ground contact), commonly available at places like Home Depot. I don't think it's a good idea to use untreated wood on something like a tractor, that's always exposed to weather. I also read an article by an expert, who says exposed treated wood will last a lot longer if an annual water repellant is applied, something like Thompsons Water Seal.
The skid system and the main bottom frame would both be constructed from regular ground contact pressure treated 2x8's from Home Depot, that's easier and less expensive than rough cut lumber.
Initial construction of the skid and lower frame, is best done by elevating the frame and skid systems, to make them easier to work on, we used 5 gallon buckets in this photo. I would build the skid system, and attach the main frame to it, before adding any super structure to the tractor.
It's incredibly convenient, being able to lift and flip the frame and skid system at will. With a little help from others, it's easy to do.
An easy way to make sure the frame is square, you must do that before attaching the scaffold bracing, which locks it in, is to make sure the diagonal measurement between both sets of corners is same. If the frame is level, and both diagonal measurements are the same, you know the frame is square, that's important.
Here's the Heavy Flying Fortress frame being constructed. You can tell the frame is right side up because the upper level scaffold braces, which are covered in white PVC pipe, are on top.
The PVC pipe will be wrapped in Gorilla Tape (duct tape on steroids), it's worth doing, the chickens love to perch on the pipe and look out through all the open wire, on all sides of the tractor.
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