Problems with teaching choir music...

I have begun teaching sectionals in 6th grade choir. Some of these young musicians can barely follow a score, and have just begun getting a taste of reading/ear training exercises from my cooperating teacher and myself. Sometimes unfortunately in order make progress learning our pieces for the winter concert we simply go over rhythms and then end up Rote teaching portions of the piece. This is extremely frustrating because I know that this is not how I want the students to learn their music, especially because it creates a teacher centered environment and does not allow the students to develop independent musicianship. These are sixth graders new to the school and for the most part new to being able to have thier own octavo to follow, and unless they have been taking private lessons, most are unsure of reading in general. I am posting this because I am looking for insight as to how I can help them build their own musicianship and skills without ignoring the task at hand (AKA concert preparation), and not bore the choir or cause them frustration. We have gone over some rhythmic reading exercises and have been discussing how to mark music and follow a score, but I feel like it is still a disconnect from the music we are performing. Any ideas?