Does your HS have an area or interest in having their own chickens? Maybe this ties in with some classes (ag, animal science, food science, home ec, etc). You could build a walk in coop for say 10 -12 chickens. Of course, this may not be allowed or supported at the HS, but could be an option. I know some schools do have gardens and animals like chickens.
an A-frame is not going to be very good for WI weather. However, an elevated coop (like you might buy at Tractor Supply) could be built better than those pre-fabs (that is bought at TSC), and you can send them home with the plans for the attached run to build themselves if time only allows for building the coop. For a coop for 4 chickens you need a 4x4 interior floor (not counting nest boxes) and a 4x10 run or approx 40sq ft. For 6 chickens you need a 6x4 interior. The 4x4 interior makes better use of your materials as most plywood etc comes in 4x8 sheets. Also, what are town ordinances and allowances for chickens in your area from which the HS pulls? If most everyone is allowed 4 chickens, then you can aim for that number.
Supplies: Can you get the support of a local company to provide you with the materials at a reduced cost - since you don't want to have to charge too much for the "chicken Kit Day", but a local company may support you in this as it is for your senior project. Will they provide you with an experienced helper so the novice learners can get through the building phase at a reasonable pace?
Good Luck - and sounds like a fun project.