Large Tractor Coop




Introduction: Large Tractor Coop

Most tractor coops plans that I have looked at were rated at no more than 8 chickens.  We ended up getting 14 chickens and I needed a tractor coop big enough to house them and light enough that it could be moved around.  I had seen a photo of a coop that looked sort of like a stage coach with a screened run below it.  The finished product that I ended up with is seen in the photo. 

The coop is 8 ft long, 4 ft wide, and 4 ft high (plus the roof).  The nest box attachment add about 2 feet on one end and has three nest compartments.  The watering system consists of a kitty litter bucket on the roof that feeds water via vinyl tubing to a PVC pipe that has four chicken nipples installed in it.  The main floor of the coop consists of half inch hardware cloth that lets the dropping fall through to the ground below.  There is a removable ladder through an opening of the hardware cloth that lets the chicken go down to the ground below to eat grass and bugs.  The whole structure rests on four 10-inch wheels.  In the main compartment there are four 4 ft perches mounted laterally across the side walls.  There is a drop-down door on the back of the nest boxes for access to the eggs.

The coop is comfortably large enough for the 14 chickens.  I was worried about them not having enough roosting space with the 16 feet of perch but it's actually too much.  One time I had seen 12 birds perched on one four foot bar.  I also knew that the 32 square foot of screened ground below the coop is not nearly enough space for the chickens to roam around it.  My plan was to release them regularly from the coop to roam where they want.  The entire coop is surrounded by a 165 ft portable electric netting fence that is energized by a solar charger.  The purpose of the electric fence is to keep predators out and not keep the chickens in.

Step 1: Planning the Framework

Since I am somewhat of a klutzy carpenter, I decided to go with a basic structure that was strong and forgiving of mistakes. I wanted something that was strong enough and rigid enough that I could hang things on it.  I decided upon four 4-ft long pressure treated 4x4's to serve as the corner posts.  These were connected to each other by 2x4's and 1x4's.  These connecting boards determine the length and width of the coop.  Since I was shooting for the max to house 14 chickens, I made these connecting boards either 8 foot for the length or 4 foot for the width.  By attaching all these together with nuts and bolts, I was able to get a very rigid structure.  With that in place, I could add sides, a main floor, a nest box, a roof, and wheels. 

Materials needed:

* 2 8-ft pressure treated 4x4's (cut these into 4-ft lengths)
* 2x4's
* 1x4's
* Sheets of 3/8's inch exterior plywood
* 4 10-inch or larger wheels
* Bolts, washers, and nuts
* Deck screws of several lengths
* Lag screws
* Primer paint and exterior paint
* Half-inch hardware cloth for the flooring and for the fenced in bottom run
* 3 foot of allthread pipe for the axles (diameter determined by the hub of the wheels)
* Plexiglas for windows (optional)

I think I paid around $100 for the materials.  It would have been more but I got a great deal on a sale at Harbor Freight for the wheels and was able to take advantage of various materials I had laying around.  You are going to pay the going price for wood.  I paid a lot at Lowe's and Home Depot for hardware such as large bolts.  I later discovered that you can buy these in bulk at Tractor Supply where they sell nuts, bolts, washers, and lag screws  at $1.99 a pound.  (This obviously refers to purchases in the US and maybe Canada).
I wouldn't go out and buy all these materials at once based on my list.  I'd start out with what's needed for the basic shell and then get more materials as you make your personal adaptations.

Step 2: Assemble the Frame

1. Start by building the side frames.  Cut your 4x4 posts in half so that you end up with 4 posts that are 4 ft long.  Then for one side attach a 2x4 to two of these posts where the 2x4 is flush with the top of the posts.  I did this by drilling a hole through the 2x4 and the 4x4 just large enough to insert a 6 inch long 3/8ths inch bolt.  This connection is critical to the strength of the whole coop.  The actual depth of this hole will be 3.5 inches plus 1.5 inches or 5 inches total.  A six inch bolt is the shortest one available to accommodate the nut, bolt, and washers.   I would recommend not using the full 8 ft of the 2x4 because the actual length of the coop will be extended by boards that connect the two long sides together.  I recommend that you keep the length of these boards to about 92 inches.

2. Attach a second 2x4 to the two posts about 15 inches from the bottom of the posts.  This 2x4 will be the foundation for the floor of the coop.  Where you put it will determine how much clearance  there is between the floor and the roof and the ground and the floor.   15 inches seemed to be a happy compromise.  Use the same 3/8ths inch nuts and bolts for this connection as well.

3. Build the other side frame with the other 2 posts.

4. Attach the two side frames together with 2x4s cut to 46 inches (48 inches will cause problems later).  Ignore the fact that I didn't use a 2x4 across the top on the sides.  If I had to do it over again, I would have done it that way.  You probably should use lag screws to attach these 2x4s to the posts.  I used deck screws but ran into constant problems with the screws being stripped.  With lag screws you can tighten down with a wrench.  You will have to pre-drill the holes for the lag screws. 

5. Once you have the box assembled, make sure it is square in all directions and then tighten down so that it is rigid.  

Now you have foundation of a tractor coop that you can add everything else to.

Step 3: Add the Cross Braces for the Floor and Top

1. The floor of the coop will be half inch hardware cloth supported by braces.  I used five 1x4s cut to fit snugly within the side 2x4s.  These boards should be oriented vertically to keep the floor rigid.  I predrilled from outside the 2x4x into the ends of the 1x4s so that I could use deck screws to hold each board in place.  The first and last 1x4 can also be attached to the inside of the corner posts.  The other three should be spaced out evenly. 

2. Use 4 1x4s to connect the top 2x4s.  This will give the whole frame additional rigidity.  These will be laid flat across the top 2x4s. 

3.  Use a 2x4 down the middle of the top side of these 1x4s.  The 2x4 will be oriented vertically.  This will give minor slope to the roof.  The roof plywood sheets will be attached to this 2x4.

Step 4: Install the Floor

1. Run two 1x4s along the top of the floor braces.  If you made your side 2x4s shorter than 96 inches, these boards should span the entire length of the coop.  Attach these boards with deck screws.  Plan where you place these boards based on where the overlap of hardware cloth will be.

2. Use lengths of half hardware cloth to cover the entire floor of the coop.  Hardware cloth comes in 24 and 30 inch widths.  You will have to overlap two stretches of hardware cloth to cover the whole width of the coop.  Where two pieces overlap, there is a chance that the floor will sag unless one of the long 1x4s is under it.  Make sure that the two edges of the overlap are secured so that the chickens don't snag themselves on it.  I mainly solved this problem with the generous use of short zip ties.

3. cut a hole somewhere in the hardware cloth big enough to fit a ladder down to the lower part of the coop.  The ladder I built was simply a board with cross strips spaced about six inches apart.  I originally had this ladder hinged to a cross member above with a string going down to let me raise the ladder from the outside when I wanted to move the coop.  In short time the chickens pecked the rope apart.  My better solution was to simply lay the top end of the ladder across a cross member on the floor let it slant down to the ground.  I lift the ladder out and away whenever I want to move the coop.

You might consider a plywood floor instead of hardware cloth but I have found that with hardware cloth there is very little buildup of droppings.  Even when there is some, it gets broken up and falls through to the ground as the chickens walk on it.  If you use a solid floor, you will have a constant and distasteful maintenance issue.  

Step 5: Attach the Wheels

I purchased four 10 inch wheels from Harbor Freight.  These wheels had pneumatic inner tubes in them.  To make an axle for each wheel, I bought a 36 inch piece of allthread bar from Lowes.  I chose a diameter that fit through the hole in the wheel.  I could think of no other way to create an axle for each wheel.  If you have a better idea, use it.  This solution seems to work.

1. Cut the allthread bar into 4 9-inch sections with a hacksaw (tedious!).  Actually 9 inches may be a little long for what we need but the excess can stick out on the inside of the post. 

2. Drill a hole through each 4x4 corner post about 2-3 inches from the bottom of the post.  This hole should be just big enough to fit the althread bar through. 

3. Insert the althread bar for one wheel and have it poke through the outer side to accommodate the nuts and washers that will be used.  This is easily adjusted while you adding the various nuts and washers and the wheel. 

4. Attach a nut and washer to the inside part of the bar to trap the bar from the inside and to measure how much sticks out the other end.

5. On the outside use a washer and a nut to anchor the bar in place and tightened to the post. 

6.  Put the wheel on the bar and use a lock nut to trap it firmly in place.

7.  Make adjustments as necessary to all the nuts so that the bar is firmly attached to the post and that the wheel is held just loose enough that it can roll easily.

Note: Mounting these wheels is a tricky process because the basic frame is already quite heavy.  I managed by tipping the frame partially over on its side.  Once you finish one side, it's even trickier because it will tend to roll once the one set of wheels are on the ground.  The alternative would have been to attach the wheels to the posts before you start but that brings on a whole set of other problems with the frame constantly trying to roll around. 

Step 6: Attach the Sides

1. Cut 8 1x4 boards (you can see I used plywood but 1x4s would be better) long enough to cover from the bottom of side 2x4 at floor level to the top of the top 2x4. 

2. Attach each of these 1x4s to either side of the frame on the inside of the lateral 2x4s with short deck screws.  Space them out evenly. These boards will be used to attach the roost mounts to and to support side panels and doors.

3. Decide how many doors and wall sections you will have on the long sides of the coop.  I decided to use four drop-down doors.  It's important to have doors all around so that you can reach inside from everywhere to perform maintenance functions.  In the middle of each side I had a solid piece separating the doors.  On one side it was a piece of plywood and on the other side I place a section of plexiglas so that we could see what was happening inside when the doors were shut.

4. I had two old storm doors from which I removed the long piano hinges.  I cut each of these in half and used them for the four doors.  They work perfectly.  If you don't have these, you will have to use 2 hinges per door.

5. I added the nesting extension to one end of the coop.  On the other end I used plexiglas so that we could look in.  One problem with this in the summer is the sun will beat in if you point that end to the south.

Step 7: Add the Perches

I created four perches made out of 2x4s that spanned the width of the coop.  Based on what recommendations out there, that seemed to be what I need for 14 chickens.  However, I have found that three perches would probably be fine.

I designed a setup where the perches are simply held in by gravity.  I took 4 inch sections of a 1x4 and cut a U-shaped hole on one end.  These cleats were attached with deck screws to  the vertical struts that go from the two main 2x4s running along the side.  I then simply dropped a 2x4 vertically oriented into the the two opposing cleats.  I had to give enough wiggle room so that they would drop in easily.  In some cases the wiggle was a little too much and let the perches wobble a little. I had intended to put shims in there to make it more steady but didn't and the birds don't seem to have any problem with it.

You can see in one of the photos our 5 year old grandson sanding the edges of the 2x4 perches.  That was more of an activity for him that a necessity for the chickens.  He also helped me with a lot of priming of the various pieces of coop. 

Step 8: Create the Bottom Run

The area below the floor was intended as a chicken run that the chickens would have access at all times.  To keep the chickens in, I needed to surround the bottom run area with hardware cloth.  I used four 1x4s to create a bottom skirt around the coop to which I could attach the bottom part of the hardware cloth.  The boards for the long sides of the skirt need to be attached to the insides of the posts so as not to interfere with the wheels.  The ones on the ends can go inside or outside.

The hardware cloth is attached from the 2x4s at floor level down to the skirt with fender washers and desk screws.

One very major mistake I made with this design is that I made the skirts as low as possible (something like a half inch from the ground).  The problem with this is that there is absolutely no clearance between this skirt and bumps and tall grass.  As a retrofit, I removed the bottom hardware cloth and raised the skirt about 3 inches.  When the skirt boards were lower, it was virtually impossible to push the coop across the field.  After the fix, it is possible for our three grandsons (now 6, 8, and 10) to do it by themselves.

I had originally put a sliding door at one end of the coop down at the bottom level.  This seemed like a good idea but the door kept sticking on me and I eventually got rid of it and replaced it with hardware cloth.  When we let the chickens out of the coop to run around, we simply open the door nearest the ladder in the floor and they come streaming up the ladder and out of the coop. 

Step 9: Roof

The roof consists of 2 4x8 sheets of plywood (3/8ths in thick).  Each piece of plywood is screws to the 2x4 running down the middle of the roof support boards and attached to the sides of the coop. 

Run a bead of caulk down the crack where the two sheets of plywood meet. 

The plywood should be primed and then painted with exterior paint with several coats.  There is no need for shingles or anything like that.  This roof has never leaked.

Note that there are opening at each end of the coop under the plywood.  Don't seal these opening because they are needed for ventilation.

Step 10: Add the Nest Box

The nest box is essentially a frame that is suspended from the corner posts at one end of the coop.  Since the nest box is not more than 18 inches deep, not that much weight is hanging from these posts.  The roof of the nest box is attached to the board supporting the roof.  Originally, the roof was going to lift up on hinges but the hinges were not easy to attach and it occurred to me that our grandchildren would not be tall enough to reach over the back wall and collect the eggs.  The roof remains fixed in place and the back wall drops down.  The only thing keeping this back door in place is that it is trapped by the font end of the roof.  A couple of times the wind has caught the back door and opened it.  I need to put a simple latch on it.

I divided the nest box into three nesting areas.  to support the divider walls, I used shelf angle brackets.  The inside opening to nest boxes is flush with the floor of the coop.  I added a four inch tall board across this opening along the bottom to keep the nesting straw from going into the coop itself.  This actually serves another benefit: it gives the chickens a little more privacy while laying their eggs.  This is actually recommended by chicken experts.  It is better that the nest boxes be somewhat closed in and dark.

Step 11: Watering System

The watering system for the coop uses chicken nipples.  It's impossible to find these at Tractor Supply (they've never heard of them).  When the chicks were small, I had a terrible experience with the watering cup I bought from Tractor Supply.  I would provide clean water and within five minutes it would be filled with droppings and pine shavings.

Chicken nipples are small red valves that screw into a bottle or pipe and have a shiny lever at the other end.  When a chicken pecks at the lever, a drop of water forms.  Initially, I screwed one of these into the bottom of a bicycle water bottle.  The fear is that chickens will not learn to use it.  Within 30 seconds of me putting it in the brooder, the first curious chick pecked at it and got a drop of water.  Within two minutes, all 14 chicks were getting the water. 

The system in the coop involves putting a kitty litter bucket on the roof of the coop.  I installed an adapter to the lower side of the bucket that is made to fit a vinyl tube.  The vinyl tube feeds down into PVC pipe setup.  The vinyl tube connects to a barbed connector that screws into a tee fitting for the PVC pipe.  Two short sections of PVC are inserted horizontally the tee and each of these sections are then capped.  Each of these small sections have two chicken nipples screwed into it. 

This system works very well.  This is the only source of water for 14 chickens.  If they are roaming around the yard and get thirsty, you will see them jump/fly into the coop and get a drink and then leave again.  This is much better than any watering bucket that  has be be cleaned out regularly. 

There are a few issues with this system but they far out weigh a watering trough.  The bucket on the roof splashes water when we move the coop.  It doesn't slide off because it is wedged in with wooden cleats, however.  Another issue is that it is very difficult to get a leak proof fit with the chicken nipples, especially into the rounded side of a PVC pipe.  However, the occasional drip just goes straight through the floor to the ground.  It's also hard to fill the bucket on top.  You don't want to keep disconnecting the tube so you have to fill it with another bucket.  Even for an adult this is a little difficult.   Finally, this system has only been used during non-freezing weather.  I'll come up with another arrangement in the winter.

It took several trips to Lowe's with consultations with the plumbing people to come up with this system.  i was originally going to go with garden hose connectors but they were all so bulky.  Lowe's and stores like that care a wide range of connectors that will do the job.  Make sure you pick a diameter of vinyl tubing that works with the connectors they have.

You don't have to use a bucket like I did.  It could have been a smaller bottle or jug but it's better to find something with a flat side or bottom for a tight fit.  This bottle could be mounted on the end of the coop just above the height of the chicken nipples.  This is all gravity flow and you don't need much of an elevation difference.  Instead of using a tee-shaped arrangement of PVC pipe, it might be simpler to use an L-shaped arrangement. 

Step 12: The Coop in Operation

The coop is being used in a 3 acre field surrounded by horse fencing.  The chickens share this field with 2 Boer goats and one French Alpine.  The fencing keeps the goats in but not the chickens.  The actual chicken coop is surrounded by a 164 ft solar powered electric netting fence.   This electric fence was originally used to keep the goats in a specific area in the field before the whole horse fence was made goat proof.  We now use the fence to surround the tractor coop, not to keep the chickens in but to keep predators out.  It is only turned on when no humans are around.  When this is the case, the chickens are also made to stay in the coop.  The fence does not protect the chickens from hawks.  Herding 14 chickens into the coop is a 2 person job because the chickens wander all over the property, including outside the 3 acres.   They seem to get used to the routine.

As was mentioned before, this coop was very difficult to push across the field when the bottom skirt boards were flush with the ground.  Now one adult can push it. 

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    8 years ago

    I like your design of chicken coop. I need one because some chicken coops are very expensive some $250


    9 years ago on Step 12

    Thanks so much for this! I'm browsing for designs. Couple questions: I gather chickens share nests, if you only need 3 for 14 chickens?
    Also, re portability - what do you think about having wheels on one end, and handles on the other, so you can move it wheelbarrow-style? Weight would be an issue, maybe, with that amount of wood.
    Thanks again!


    10 years ago on Introduction

    Thanks for the post. I've looked at a number of tractor designs, and yours is the best for my needs. I live on a plateu and get quite a bit of wind. The wieght of the coop keeps it stable, and keeps preditors out. Got one complete and working on two others, then the wife wants one for the rabbits.

    Keep up the posts!


    11 years ago on Introduction

    Being that axle cutting is labor intensive why not just leave in one piece and thread through and through? I did not read why you cut them up because I like scanning more than reading.


    Reply 11 years ago on Introduction

    The allthread bar was only 36 inches long and would not be long enough. Even if it were 48 inches, it might have been a little too long or a little to short (probably too short). Cutting is labor intensive but it only took about 5-10 minutes per cut with a hack saw. Just keep reminding yourself what they had to do in the 'old days'. It's a small price to pay. Besides, I didn't have to spring for a second bar.


    11 years ago on Introduction

    This is by far the best I have come across so far and very well explained. It could even be converted to keeping pet rabbits.

    Thank you very much :)


    11 years ago on Introduction

    If you don't need one this large, you can always scale it down.