The IN and OUT of my coop, please advise

[SurferchickinSB]

Putting some finishing touches on our shed turned into coop. Have a few ideas but need your guidance as to how my hens will enter and exit the building.

The run is not even in construction works yet. My birds are free rangers and the run will eventually be built so that we A. do not need to get to the coop precisely at dawn before they squawk their brains out in confinement and B. so that we have a prayer of hiring the neighbor boy to care for the birds while we are taking (a hopeful) vacation. I'm sure down the road we will find other benefits to having the run as well.

My goal here is to eliminate the need to hack a chicken hole in the side of our nice Shed/Coop. Said inner shed coop contains a perfectly sized window for chickens. The run will be secured to the exterior of the shed where this window is.
Problem: height of window. 3 feet, approximate floor to sill. Outside, drop is more like 4' but I could easily remedy that with just a tree stump I think.

Conveniently, my bookcase turned into nesting boxes can be placed next to this window, making double use of any ladder/rung/ramp/etc for the window exit as they will enjoy getting to the top of this book case via said method. It is taller than the sill, so unfortunately cannot be placed underneath.

What I really need to know is:
How steep is too steep for a ramp? I did some funny maneuvers with the measuring tape and wasn't happy with the angle. Angle can be modified some by placing the ramp on a stump/log/blocks/brick/whatevers.
Can/will chickens utilize a ladder-like "ramp" to exit through the window? This would be very space saving! Consider: wood pallet set at a slight angle, the slats make nice toe grips?
Do ducks have the same ramp abilities as chickens? Say, when I acquire ducks I can overnight them inside the shed coop and know they can get back out?

Other ideas? Or give up and cut a dang hole?

I think that 3 feet is kind of high. It’s not that difficult to cut a hole just drill the four corners and use a jigsaw. You could connect your run to the side with the door and you can also get an automatic chicken coop door. That’s what I did, so I don’t have to get up super early or be home at sunset. That way my girls are not locked in the coop till late in the morning and in the evening I know they are safe if I happen to not be home. Even though I am in California, it’s sort of cold in the winter in the morning. My 4 x 8 coop opens up into my 8 x 10 run and then when I go into the yard around 8:30 or 9 AM I let them out into the larger chicken yard. Even though you plan on letting yours free range all the time, they will probably still need some sort of a covered run. When it rains mine don’t stay in the yard even though there’s trees and stuff. They always run to their run when it starts dumping rain. Mine don’t hang out in the chicken coop except to sleep and lay their eggs.