This is a logic based solution to a situation that had been raised but, not fully vetted when we first built the coop & run. I am so glad that we enlarged our original plans for "some expected expansion" that would occur down the road. I'm sure you have learned of the term "Chicken Math"? Well, here we are, down the road a wee bit & that *Math* caused this project.

This project is using leftover wood, nicknamed 'stickers' by the folks at most lumber yards. These 'stickers' are the lumber used in shipping pallet-ed & rack lumber, drywall etc. They are all ~48" long X ~2" X ~2" with a grove cut lengthwise on one side.

Really need to use a section of the coop for the Silkies. This will increase the actual runs usable footprint for all birds better. I will be adding a doggy door for Silkies to gain rotating access (with the big birds) to the small back yard later in the weeks to come.

So here is the coop space about to be used for the Silkies roosting and nesting boxes.
IMG_20201225_171156074.jpg
(West facing wall with 2'x3' window) The green material was a shower curtain, provides a nice privacy for the hens in the nesting boxes. Note the box extends out past the frame as the curtain draped out and over it... keeps poo out too. This box will be partially disassembled and cut down about 4-5 inches when I get to that stage of this project.

IMG_20201225_171109923.jpg
The Southwest corner of coop now all cleared out....

Here are the rough drawings. I'm sorry they are not 100% to scale but, realize this is "really close" to scale of 4 boxes equal 1foot Distance; 1 square is ~3" per side in all of these drawings. Graph paper allows for a lot of flexibility when designing stuff. It's very forgiving too. You don't have to draw every line the whole length either. Which allows you less to erase when roughing out your designs.
IMG_20201230_182115175~2.jpg
1st drawing, facing west, in elevation view. Added notes for the top shelf above the roosting rail, it could be hinged for lifting up and allowing easy removal of the roosting rails for cleaning and pouring pdz, etc.
IMG_20201230_182144041~2.jpg
Top down view (now 2nd redrawing) of the ramp locations from ground to roosting rails & then up to the rooftop feed & water patio. This "patio" will be almost flush to the window base frame.
IMG_20201230_182203646~2.jpg
Side view #2 (currently 2nd redraw) of ramps length & potential distances. Each square is still ~3" on a side, so 4 boxes would be ~1' long or tall.

IMG_20201230_182216542~2.jpg
This is rough details for the poop-board / roosting rails. In the right upper corner is the mini coop's exterior measurements that they are currently living in - out in the run.
This will allow me to fine tune the measurements for both the removable poop-board / roosting rails. Comparable space to what they are used to. The old adage, "measure twice & cut once" is very necessary here. I had already pre-cut the plywood bases and allowed for trimming to occur. As this was initially cut on the table saw from a single 4' X 8' sheet I didn't want to waste any more then absolutely necessary.

So here is a midway point into the build.
IMG_20201230_180136231.jpg
I have already pre-trimmed the 45° cuts on all the arms of the ramps. And mounted the mid level ~12" corner flat section for the ramps to the rooftop patio.
IMG_20201230_180142076.jpg
The 2, 8'6" tall 2x4's are hanging from rafters with ~1" floor gap for cleaning the cement floor. The "door" is either going to be 4' or 5' tall, I haven't decided which pallet side frame I'm going to use for the door yet. Sorry no before picture of it.
IMG_20201230_180152576.jpg
You can see the several 'uncut stickers' laying across the horizontal frame that is 17" off the ground -behind the row of carpender clamps. The ~45° pre-cut pieces (runners for the ramps) are much more visible here too.

IMG_20201230_180244911.jpg
The twin wide nesting box still untrimmed & the ramp needs the ribs mounted before it's attached to the triangled platform.

IMG_20201230_180328704.jpg
All the big flock are nestled in for the night, the relocated stairs are acceptable to everyone as they all walked past me and around while I kept cutting & screwing the frame together that evening.

A little time passed, this next page is to show you the planned positions of the support frame pieces. The dotted lines with the 45° dash lines inside them. The side view of the "ramp" section is showing the ribs for them to climb up the ramp & the angled cuts to allow a smooth surface to mount flush. Please remember that this design is very simple, precision is not crucial here. The goal is to have the ramp to be at an angle they can easily walk up. The angle cuts might be significantly different for each end of runners. Prime example, the upper end that gets screwed into the cross beam as compared to the other end to sit flat on the floor of the mid step plywood. The upper cuts were ~45° and the lower was closer to a ~30° if memory is correct.
IMG_20210111_000438078~2.jpg
The "ribs" that are screwed into the plywood plank are ~1" X ~1" X ~12" and are spaced about 2" apart. It's a shorter distance as they have a shorter gate then the larger flock does. The plywood plank is ~1/2" thick X ~12" wide, each ramp section was trimmed down to fit the needed lengths. The screws I had leftover are 2" long. These screws actually go into the runners on the underside of the plywood, "just enough." The runners are actually not "needed" do to plywood's thickness is so strong. They are actually to make mounting to the cross beams a snap & protect the flock from the screw tips that would be sticking through the plywood.
The prefab coop they are currently staying in has a ramp that is ~6" wide and the ribs are maybe 1/2" tall/thick? They don't enjoy walking up it and routinely slide off it.
Here are the completed step ramps from ground up to roosting rails & then the mids.
IMG_20210110_173732864.jpg
IMG_20210110_173723034.jpg
This is the same design but, goes to the nesting boxes. All parts are approx the same measurements too.
IMG_20210110_173742502.jpg

Now for the easiest part. The avian netting install. Well, I came up with a better, easier method for poop-board / roosting rail removal & cleaning. Here it is, a removable wall.
IMG_20210110_163757251~2.jpg
That piece is ~1/8" thick plywood & it slides into a gap between a 'sticker" and the plywood layer the original chicken door is mounted to. This swing-out arm keeps it from flopping out nicely.
IMG_20210110_163805760~2.jpg
IMG_20210110_173702800.jpg
Those are the two poop-board / roosting rails - finished. All the ramps are finished & installed as well.
After the 1st night it seemed to be acceptable to the Silkies:
IMG_20210113_174340937~2.jpg

The top "patio" is not screwed down as it's actually had the corners cut out to fit snugly against the vertical 'stickers' on the walls.
IMG_20210113_174257338~2.jpg

You can also see that the avian netting has also been screwed in and mostly trimmed up at this point.

Here are a few close ups of the ramps both removed and installed:
IMG_20210111_180152140.jpg
Top surface view. The next few are side views:
IMG_20210111_180204313.jpg

IMG_20210111_180212508.jpg

IMG_20210111_180224845.jpg
This is the location of it to be mounted in & the one below is it correctly installed:
IMG_20210111_180238322.jpg

The automatic chicken door install was a lot easier after I installed this first one. Here it is on the south facing wall, for the big flock when I originally built the coop last summer.
IMG_20210111_162539213.jpg

These are the steps of creating, measuring, cutting/trimming & then assembling of the west side door for the Silkies:
IMG_20210111_162514942.jpg
This hole I cut was a little wider then the 2" X 4" *H* that is to be mounted to the plywood sheet in the next frame.
IMG_20210111_162521771.jpg
IMG_20210111_162531268.jpg
Now the base requires a 2"x4" cross beam to protect the automatic door from being lifted by claws....
IMG_20210111_165236716.jpg

IMG_20210111_165241634.jpg
The next shot shows how large the hole ends up being :
IMG_20210111_165257989.jpg
Here it is finally mounted:
IMG_20210111_174323866.jpg

The door is only 5' tall so for simplicity I used the excess netting to drape over the door. (the semi-white streaks are dust particles flying at night in these shots)
IMG_20210111_175833564.jpg
These next 2 show it "flipped up" & door with the door open:
IMG_20210111_175825442.jpg

IMG_20210111_175858471.jpg

The last steps will occur over the coming weeks as of today 1/10/21.
A) [x] cut outside swing-up door; [ _ ] mount hinge and [X] the stair steps on both sides
B) [X]re-hang the privacy curtain back over the nesting boxes (both the trimmed pair for Silkies and the 3 for the larger hens)
IMG_20210113_174202219~2.jpg
IMG_20210113_174228594~2.jpg
IMG_20210113_174314352~2.jpg
C) [X] fill the poop-boards & reinstall them
D) finish the netting attachment around the window so that it can be open 3/4 of the year and the flocks stay separate

These last tasks will likely be additional posts to this article in the coming months:
E) [1/2 X] re-position the inner run separation fence panels (half way done. Enough to put them in the coop tonight 1/12/21)
F) mount the doggy door to the small backyard fence for the Silkies to gain access to the yard...