Has anyone ever used a product called 'Flock Block'. My wife went shopping today and I ask her to get a bag of feather fixer, well, she come home with a flock block. Seems the salesman talked her into it. We have a few chickens that have been rooster worn and need fixin'. I removed the roosters to a different pen, now there are no roosters in with the hens. I wanted to add feather fixer to the feed to help with the saddle feathers but ended up with flock block. Any thoughts on this would be appreciated. I've never used flock block before.