Effects of Hard and Soft Scalding on Defeathering and Carcass Quality of Different Breeds of Chickens.

Abstract

Current soft scalding in broilers is not applicable to various strains of chickens with different market weights and ages. This study aimed to examine the effectiveness of soft (57 °C for 120 s) and hard (60 °C for 60 s) scalding on defeathering and carcass quality of the local strain of Red Feather (RF) country chickens and determine age, breed, and body weight factor in accounting for the defeathering effectiveness using adult layers and juvenile broilers as a reference. Results showed no differences between soft and hard scalding in broilers with 60% and 80% of acceptable defeathering scores, respectively, while a significantly better effect by hard scalding was observed in adult layers, young and old RF chickens with more than 70% of birds exhibiting desirable scores and less than 20% by soft scalding. In contrast to soft scalding, hard scalding had no significant effects on breast meat color but impaired skin color in broilers as assessed by L*, a*, and b* value analysis. Interestingly, hard scalding increased breast skin yellowness and lightness in young RF chickens and lightness in old RF chickens, while there were no significant changes in layers. However, hard scalding decreased skin elasticity in layers and old RF chickens. The effectiveness of defeathering by scalding method was governed by the age to reach a certain threshold in the development of dermal architecture and feather richness, irrelevant to body weight. The alteration of carcass color primarily depends on age, body weight/breed, and their interaction. In conclusion, current soft scalding is suitable for broiler chickens for desirable defeathering effect and carcass color, whereas layers and RF chickens scaled at 60 °C for 60 s showed a better defeathering effect without unfavorable changes of breast meat and skin color.