Straw is not a good idea. Temporary but not a permanent fix. Sand is great, wood chips also work well. Add lawn clippings after you mow every time. Its a cheap form of bedding in the summer
I would just leave them in a brooder with the lamp. With a heat source, the hen isnt required. They will do just fine on their own. That will eliminate any chance of injury or otherwise
I have a red heeler. They do a good job. As far as breed specific, mostly just training. I also have two pitbulls. Needless to say, my property is pretty much predator free. Haha
They are pretty quiet. Soft clucking. They are very "bossy" though. I have 50 other chickens and they are the most curious. Almost nuisance-like most times. Haha