Sean,

I have been breeding rats for a while I have a breeding colony of a bout 75. I feed Muzzri 6f just went and got two new bags a week or so ago. Walked in last night to 3 dead rats different ages, different sexes different ages, different tubs, called around and this thread came up. I came out this morning and 3 more dead. I am scrambling to get this under control I have moved them to a meal mix of my own but I fear the damage is done.

Any help would be hot.