I am sure you meant 40 quart tub not 40 gallon tub but thats really big for any BP except the largest 2500-3000g+ females. If he is balling up when offered that is a sign of stress. I bet a smaller container will help. We keep ours in Freedom Breeder racks and they stay in FB10 tubs until about 500g which measure 21.5"L x 9.25"w x 3.5" high. We have moved 1200-1500 girls from the FB40 tubs to the FB70 tubs and had them go off feed due to the larger size. They thrive in tighter enclosures. We have found the best feeding responses with 88-89 hotspots with a warm side ambient temperature of 84-86 and cool side at 78-80 with 70-75% humidity. I hope this helps!