Honestly an awful lot of people find that the predator that ends up killing one (or all) of their chickens is their good dog who has hitherto guarded them religiously. So be cautious.
But, that said, if you have a dog out there with them and it's just for daytime use I can't see what point...
Being as it is relatively well established that a single strand of electric will only keep "most" coons out of a corn patch, I have a lot of trouble believing that it would be more than "sort of" successful in keeping them out of a chicken patch. And the only dogs/coyotes it will scare away are...