Depending on where your bok choy (and similar Asian veggies) comes from, do be sure to soak it then rinse before serving!
For Cairo, I chop it like mad so that the leaf bleeds (? I forget how to say in English now) and sticks to his other veggies/fruits. Other times, I thread a hemp twine through it (specifically xiao bai cai, not the Western-sized bok choy) and hang it from the top of his cage - he gets so excited to tear it to shreds and really bite into the meaty part, then it falls to the bottom of his cage where he finishes it off! It turns into more toy than food, but he still eats a bit and it's great fun for an afternoon treat.