Rats vs rats
Arnold Trachtenberg (Fri, 03 Sep 2004 14:00:40 PDT)

Jane et al:

I have heard that there are some rodenticides that don't allow secondary
poisoning such as was described in the death of the borzoi. I think it
may be zinc phosphide that reacts with the acid in the gastrointestinal
tract and releases a gas that poisons the rodent. The gas does its
thing and then moves on and secondary poisoning is not a problem. Of
course I would be hesitant about this until I had researched it a bit more.

I will do a bit of looking and report back

Arnold
New Jersey