I was advised by the elders that wool fleece as mulch ought to be buried. so the birds can't steal it. Used as a lining in the nests makes it sound quite cosy, but it upsets the humidity and throws off the hatching percentages, and our birds need all the help they can get.
Quote from the post above: Maybe use it Ruth Stout style and use it as an under-layer with a heavier mulch, like cut grass, on top.
Sounds like sense
