Ridecamp: [RC] Beat pulp & rubber tires!

I have been feeding beat pulp to two of our three horses and have been very pleased.  However, I had an incident that has left me worried about feeding them shredded beat pulp.  I found a shredded tire chunk within the mix.  I know they shred rubber tires for riding arenas and probably other things.  It's obvious whoever does their shredding did not clean out the shredder very good and it is being used for multiple uses.  Has anyone else had this problem?  Kind of scary to think my horses could have choked on a tire piece if I had not found it.  Deejay (Debi)