Atkins, J.W., & Brightling, A. (1985). The management of sheep burial pits. Australian Veterinary Journal, 62 (10), 347-348.
gives another case study in mass burial. (It’s partially available here.)
The trenches used were 3.5 meters deep. The authors estimate that 8-10 sheep (merinos, fairly recently sheared, after a period of drought) fit in one cubic meter of grave, although this appears not to have been based on any direct measurement. This number is in reference to the volume of the carcass mass only. Including the overburden, the total excavated volume was 0.3 cubic meters per sheep, or 3.33 sheep per cubic meter. The authors note that more space may be needed for other types of sheep, or under different conditions, but they consider the standard recommendation of 1.5 cubic meters per sheep to be excessive.
As these sheep were drought affected (and consequently had to be killed) it’s likely that they were emaciated to at least the same degree as the Jews allegedly killed at the Reinhardt camps. Most of the sheep were in store condition, where “it is easy to press between each bone.” (See also here. As this is not a degree of emaciation that acutely threatens the sheep’s life, it is unclear why the sheep had to be destroyed; perhaps there were other effects of the drought as well.)
The sheep in Figure 2 certainly do not appear to be larger than people – quite the contrary. Therefore this study offers yet another confirmation of revisionist statements on attainable densities in mass burial (8 humans per cubic meter maximum), and another refutation of the densities claimed by holocaust traditionalists (well over 20 humans per cubic meter).
Also of some interest are the facts that sites with clay soil were generally used, and that “disposal of carcases by burning was not considered feasible as sufficient quantities of solid fuel were not readily available.”