I believe the dogs should always be supervised with toys, unless it is something that the owner knows the dog won't eat (Some dogs need toys to keep them busy while the owner is gone). My neighbor's dog constantly ate the frayed rope at the ends of his rope toy. It always worried me because I knew it could get stuck in his intestines and kill him...I guess that was only one thing to worry about with him..the constant mites, ear infections, roaming, and neck troubles due to tugging on his tie-out were just a few of the other things...