I would say that it is probably okay to use with the dog or cat dosage for chickens. Even pedialyte for babies is okay for chickens. Some even use Gatorade in emergencies. Just make sure to follow label directions, and electrolytes are meant for short term use, such as 2 days or a a couple of days a week in hot weather.
I would'nt use it, because i never really needed it, but if t's not mean't for chickens, then dont use it for chickens, that's one of my motto's, and there is things like the chick saver thing too.