Carob (Ceratonia siliqua) is commonly found in the Mediterranean region and may be used as an alternative feed resource in livestock production. However, carob contains plant secondary compounds, such as polyphenols, which limit its use due to potential toxicity problems. This study aimed to investigate whether the substitution of barley by carob pulp at a relatively high level of up to 35% causes production-level reduction and has detrimental effects on animal welfare. Lamb performance parameters such as feed intake, liveweight and carcass weight were recorded and feeding behaviour was monitored. Blood metabolites and protein profiles were determined to detect signs of metabolic distress. The inclusion of carob pulp resulted in similar level of performance by animals in all the experimental diets. However, the feeding pattern was different with feed intake being significantly lower during the first 90 min post feed supply in the carob-fed lambs compared with the Control animals, although total daily intake was similar. In terms of welfare indicators, the inclusion of carob pulp in the lambs’ diet reduced blood cholesterol while increasing both non-esterified fatty acid and urea levels. These indicate that the animals were probably under some form of metabolic stress but not at a level to cause concerns, as confirmed by the similar serum protein profile especially in terms of albumin to globulins ratio