Manitou Auctions, Ace Powell, Quiet Herd, oil, 28 x 48. Estimate: $8,000-$12,000. ← Previous Next → Manitou Auctions, Ace Powell, Quiet Herd, oil, 28 x 48. Estimate: $8,000-$12,000. Manitou Auctions, Ace Powell, Quiet Herd, oil, 28 x 48. Estimate: $8,000-$12,000.