@seets This person should be reported to the authorities immediately imo. You are not only cruel OP, but you are a complete narcissist for only worrying about your sleep, and not the wellbeing of the dog.
@seets What in the fuck is an "outside" dog? Dogs should never be outside unattended, period. It sounds to me more like you are abusing your dog and probably shouldn't have one at all. I hope the dog keeps barking, you deserve it.
@mattyp Ok first thing, dont introduce your dog to guinea pigs. Let them co exist. Once he acts as if they are unimportant, and hes not interested, thats when I might let him go check them out.
Second, kennel your dog. I would recommend a ruff tuff so he cant hurt himself, and he cant...