If you want to order the owl pellets yourself, you can get a set of five or a set of 30 - depending on how many students you have. I had six of them, so we were able to work in small groups.
There might be an odd smell in your room when you are working on these, so make sure to have some spray on hand. Also - if you have students with pet dander allergies they could flair up. One way to combat this is to have everyone wear face masks (which gives it a more "important" and scientific feel anyway!).
If you've done owl pellets in your classroom before, I'd love to hear how it went or any other suggestions you may have in the comments below!