Making your own targets out of substantially hardened steel would be an option.
When I first started shooting silhouette, the steel was of a mild variety. The target were set facing one direction for one match, and the opposite direction on the next day.
At the end of the day, the chickens had a noticeable bend to them.
The last I heard, a set of 22 Silhouette targets were around $500. A set for your purpose would be substantially higher.