Many clay pigeons are biodegradable. The traditional kind, which contains talc and petroleum resin, does not biodegrade. While the talc is harmless, the resin/pitch and paint can be toxic to certain animals, like hogs. Biodegradable clay pigeons are made out of natural ingredients like pine resin, and they will break down completely over the course of a couple of years. Some shooters believe the old type of targets were easier to break than bio birds, but scores keep going up, not down, as shooters and equipment improve.