For whatever this is worth ...
natural fibers are a good thing, however ... polyesther batting or yarn is not a good thing for wild things.
It doesn't protect the nests good enough for the babies to stay warm.
Dog hair may be avoided because it is DOG hair, but more than likely, it may be that the dog has been shampooed?
Wildlife does not like Irish Spring, lemon, or mint ... a dryer sheet can repel a lot of our little beasties ...
I have spent years only knitting and crocheting with polyesther/acrylic yarn because one of my baby brothers was allergic to wool ... but, now that I am getting old, I am finding out why wool is such a WONDERFUL garment/blanket to live in <g>