Rupture of the gastrocnemius tendon is a costly challenge for the poultry industry due to bird culling from clinical lameness and leg condemnations at the processing plant. In this case, a broiler chicken producer experienced a dramatic increase in leg condemnations at processing, coinciding with a temporary increase in processing age and weight (from 62 days at 10.25 pounds or 4.66 kg to 67 days at 11 pounds or 5 kg body weight). Gross lesions in the condemned limbs included acute rupture of the gastrocnemius tendon with corresponding hemorrhage and edema. Histologic analysis, however, revealed that the “tendon rupture” observed grossly was in fact due to rupture of the gastrocnemius muscle at the myotendinous junction. The myopathic lesions, as well as the venous inflammation (phlebitis) and lipid infiltrates, observed in the affected tissues were consistent with wooden breast syndrome (WBS), which more typically manifests in the pectoral (breast) muscle. WBS in breast muscle and meat is well recognized as a significant problem in the poultry industry due to economic losses from breast meat condemnation. This report demonstrates that the negative bird health effects and economic impact of WBS are likely far greater than previously understood. Moving forward, WBS myopathy and vasculopathy must now also be considered as a potential cause for clinical lameness, gastrocnemius muscle-tendon rupture, and economic losses from leg condemnation in broiler chickens, particularly in birds raised to roaster weights.