With deep litter never had a problem vast majority went into the deep litter.
Other fanciers gave it to the allotment gardeners.
Coarse, sea and fly fished all my life, heard numerous different baits and ground baits used from the boiled potato we used at the Peterborough Cut in the 50s to the boilies of today that include everything imaginable, but would never have thought of pigeon droppings.
Do not know what the commercial boys will come up with next.
Regards.