You have some naughty birds - I use the same cups and have not had any issues like you are having. Definitely start engaging that energy and curiosity with some other outlets - did you get some good ideas in your quest for entertainment suggestions? Is their coop attached to a run and, if so, is the run shaded for most of the day or is it mostly full sun? A hot sunny run is likely to push them to stay inside more during the day, making the cups their source of entertainment.....