I have never thought to put dog hair out in a bird feeder. Although I might have a wee tad to much hair, especially after a busy day of grooming. I can easily fill a large bin bag depending upon which dogs have been to me for their grooming session.
I stuffed some ducks' down into the conifer tree for the birds to help themselves but probably it would have been better to put it into a feeder. However, the birds have taken it all anyway but mostly they have done it when I haven't been looking! LOL