3 science courses? Books or ebooks?

It is so hard when there are so many great options!

Personally I would just do the coop science and then maybe add Outdoor Secrets books as free reads because they are great books.

I did Outdoor Secrets when my older two were in 1st and PreK and we really enjoyed it a lot! I found all the books used most for only a few dollars, but some were out of print and more but worth it. When my youngest was getting to the kinder/1st grade point I wanted to do it again, but we had already settled into a good routine and rythem with Apologia Elementary Science for the older ones so I let Outdoor Secrets go. It was hard, I really liked it but I wanted to keep lessons short and do fewer things well instead of multiple things stressed out. It was a good year!

Another option is to do the bird book over the course of a few summers, do a lesson or two a week through the summer to encourage year round nature study. You could also look at the book list for both SCM science guides and create a free read list from the library and pick up those books and read for pleasure. The SCM guides are so reasonably priced you could even get the guide to help guide conversations after reading the books, but not do the full curriculum, just read those books for pleasure.