Slatted shutters will do next to nothing; solid shutters would give a *bit* of insulation but not a whole lot unless you construct them very, very carefully to fit tightly all round the edge and down the middle.
As others have said, you'd get much more value by just making a styrofoam panel that fits into the windows and you put it in every evening and remove every morning. Just glue (using foam-safe glue!) some foamboard to a piece of masonite or suchlike, with hook eyes to hang it from at the top.
If you would prefer a lower-labor more transparent solution: Can your chickens really *access* all the windows, like b/c there are roosts in front of all of 'em or something? If they can't reach it they can't peck, and you can just tape up clear film or (for better insulation) bubblewrap (use the stuff with big bubbles, and put it bubble side towards the glass).
If somehow they *can* stand at all windows and peck, I'd suggest screwing on plexiglass type stuff (from the inside) wherever the chickens can reach, and taping on bubblewrap as per above for all the upper parts of the windows.
Actually you *can* plastic-wrap windows fairly well from the outside without staplegunning, btw. What you need to do is staple the plastic (and use translucent 6 mil construction type sheeting, not window film) to strips of 1x2 or 1x3, like a frame but not connected at the corners so you can stretch it. Then screw this to the outside of your window framing/trim - you will only need like 2 screws on each side, won't mess up the trim much at all. Ta da. The plastic itself may not last more than one season but it is easy to replace for next year if necessary.
BTW, is your ceiling insulated. If it is, then windows are the place to focus for further insulation work; however if your ceiling does not have the equivalent of R20 or so, you will get more benefit from addressing that first.
Good luck,
Pat