I maxed out the courage of one slave to 55(current max ) and somehow it is showing lack of courage message where as my characters with less courage are not getting this message 

60 courage is needed to prevent the 50-75% reduction of food during hunting. The condition includes a random condition related to courage, so a slave with 55 courage will receive the penalty about 32% of the time on average. A slave with 0 courage will receive the penalty about 45% of the time on average. Thus Random Number Generation(RNG) is the dominant reason for the difference in outcomes.