I know that it has already been errata'ed to a -2 morale penalty.
Had there been no errata though, given the original description of troglodyte stench, it had a 10-round duration so I would have said that the effects from the stench of multiple troglodytes would overlap but not stack, i.e., the highest 1d6 Strength damage result would apply for its 10-round duration followed by the next highest 1d6 result from a stench started after the first one for the remainder of its 10-round duration, and so on.
In short, the strongest Strength penalty would take effect until it expired.
Example:
1: <----3---->
2: --<----4---->
3: -----<----1---->
4: ----------<----2---->
In the given example, you would have -3 Strength until the second stench took effect, -4 Strength for its duration, and -2 Strength until it expired. The third troglodyte stench would not take effect since the higher penalties from the second and fourth troglodyte stenches overlapped.
I like the errata'ed version better, since it's a heck of a lot easier to keep track of a static morale penalty than a variable Strength penalty.
