Pick a side of the run and cut a hole so that the door and ramp extend down into it. You can use additional hardware cloth to close any gaps between the 2. To keep them flush, maybe just run 2 2x4's in parallel so that they are above and below the door, then make a square off of those 2x4's...
Definitely the look! When my daughter saw it she immediately exclaimed that it looked like a train. With just a little more trim we could probably enhance that even more. Would be a nice, aesthetic fit for any backyard.
Fencing boards (usually 6’x6”, dog eared on one end) can also be an economical choice if pallets aren’t available or are too expensive. Plus they give a nice rustic look once weathered.
Regarding the infographic recommending both chicken feed and pellets: many of my neighbors (Utah) call...
Hens go broody when you don’t want them to… and won’t go broody when you do.