The quilt on my bed (which is what you call heavily pieced) has a Hobb's Tuscany 100% wool batt. I've washed it more than a few times in a non-agitator washer. No bearding. Wool is my preferred batting. I get better quilting definition and I love the properties of wool in that it is breathable - warm in the winter and cool in the summer. It is also a more supple batting than W&N, the drape is lovely.