Trailer Coop Framing Advice?

[SourRoses]

Hi guys, I need some input please.

We decided to make our next coop up on a trailer. It will help because we're renters and have had to leave coops behind before. At the moment we just have smaller, light coops but they are not convenient. I want a build with the features I most need... roll-out nest boxes and poop boards.

I have searched high and low for a used fully enclosed trailer in our price range, but they cost about the same as new! So here's what we're looking at buying new (picture at bottom).

Here's the question. How to get started with a frame on this?

I want to build over the sides and out the back (take the ramp off). This trailer is 5x8. So I thought I could put the nest boxes up on the side rails, poop boards above those, then the roosts. I would like the coop to be bigger than 5x8, but there's something odd with trailer prices as they seem to double just to gain a few feet.
* If we were to build out the back a bit, how far could it go and retain structural integrity? It would have less weight with the ramp taken off. I mean, even 2 feet would help, but is that going to compromise the balance of the trailer?

We wouldn't be moving this often. It might need to someday hold up to a move on the roadways, but by taking the easiest, slowest roads we could chart a route over.

I got a bunch of 4x8 boards on discount, some are really nice and I've fully painted them a nice color (to preserve them in anticipation of a build).
Our main hiccup is framing... before we go down and buy this trailer, how are we going to attach the frame and get a roof on there that could hold up to side-road speeds (with chickens inside, lol)?

 

[Sally PB]

Our main hiccup is framing... before we go down and buy this trailer, how are we going to attach the frame and get a roof on there that could hold up to side-road speeds (with chickens inside, lol)?

Our coop is built on an old trailer. I just asked hubby how he attached the frame of the coop to the trailer. He drilled holes through the vertical steel posts and bolted the 2x4s of the coop frame to them.

 

[iwltfum]

Interesting idea.. there's a farm near me that has a mobile coop in a slightly larger trailer and they use a mesh floor with hardware cloth, the poop falls right through to the land below and they move it often enough to keep it from building up in one spot. But they use other tighter winter housing so that might not be an option for you depending. Thought it was neat though.

I'm all about the coop on the trailer idea. Mine is 8x8 on skids so I can drag it around the property as needed.

There's a few things to consider with this build and weight is the number one thing for sure. The trailer is meant to hold a max weight and you really should not go over that just generally. And it would definitely be an illegal and unethical thing to do to drive an over-weight, top heavy, diy chicken coop trailer down any public roads - even if it remained drivable to do that. So that being said, you essentially need to be able to estimate the weight of your materials going into this whether you calculate as you go or draw it out and make a rough guess that way, this will be an important step. It would be a bummer to get it all built - only to walk out in the morning and realize the tires are flat and the axle is bent. Chickens, bedding, and poop, weigh a lot too. You can't ignore that weight in these calculations either.

As for getting started with a base, I would probably through bolt some 4x4s on to it as the base and then secure the floor joist system to that with structural metal ties.

Depending on the full weight and balance, you could theoretically build out the back a little, yes.