I googled it forever and couldn't find anything, so then I started a thread in the emergency section asking if anyone had a link to a sight that discussed it and someone posted a link, the link does say the benzocaine should be avoided in poultry as they can have a bad reaction to it. Others have posted on BYC of their chickens dieing immediately after a "caine" use and others have used it w/o incident. My take away from all the recent reading I have been doing is it is Russian Roulette to use the "caine" meds. Most times it may have absolutley no negative effects, but when it does it is immediately fatal w/o any chance at fixing it. I personally will not be using the "caines" and will stock non "caine" meds in my chicken first aid kit.
It really struck me the difference in medicating avian vs mammal. To question even the most common OTC first aid meds before use.