I am curious if these chucks are really box canyon chucks. Box canyon chucks should be red back or black back not granites. My chucks that you can read about on this forum were allegedly box canyons. Since they were not it brought other things into question. My dealer keeps his chucks outdoors in big sandboxes if there was not enough rocks covering the sand or they were not fed food that they would eat then that might have led to excess sand consumption or bacterial infection if the food was not kept clean during acclimation. like I said before I suspect that your chucks might have come from the same dealer as mine.