Motivating our at-risk students with an AR program

As we draw nearer to the end of our first nine weeks of school, our intervention team is looking more closely at data.  One of the first things we noticed is the number of our at-risk students that have limited amounts of AR points.  Students have plenty of time in class to take tests, but it's not happening and this makes us think they aren't reading at home at all.  We've noticed many of our fourth grade, at-risk, below-level readers bothered by having to read picture books instead of a large chapter book.  This made me wonder if the stigma of having to read certain books on a specific AR level, like picture books, turned students off of reading?  Our academic coach and myself are discussing having an AR seminar with our fourth grade students.  We want to show them incentives they'll be working for, discuss the benefits of AR, discuss any concerns they have, etc.  I'm curious to see if we have an increase in AR points over the next nine weeks after we meet with the students.