Thanks for the question, Roni. At the teacher training in February, we gave you a copy of the Ohio State University Cloverbud curriculum related to Embryology. That curriculum is designed for youth K-2. So, anything in that would be appropriate to do in the classroom with 2nd graders.
In order to make the experience somewhat real for the classroom, I would suggest you take digital pictures of the incubation process and send them to the teacher to share with the classroom. Pictures of you and your kids placing eggs in the incubator, turning them (if you aren't using an automatic turner), adding water, when the chicks start piping, when the chicks move to the incubator, etc. would be good to show. And, yes, we would most definitely recommend a visit to the classroom from chicks. Make sure you keep them warm when you move them.
Hope this is helpful. Let us know if you have additional questions.