Hi there. I'm going to provide the link to reach our dog's community where you may ask your question of our members.
http://www.medhelp.org/forums/Dogs/show/4
At the top of their page, there is a green box with "Ask a question" in it. If you click on that, a box to ask your question appears.
We are sorry about the loss of your dogs and hope that you solve what your dogs could have been poisoned with. good luck