How to carry a long zoomb when not in backpack (200-500 nikkor), with attached dslr on long backpacking hikes. So it's ready to shoot wildlife as well as keeps hands free?

Well, I realized it's not much use if camera is always stashed inside heavy backpack. It will be inside and in bad weather too, but once I spot animals I need it ready but also have hands free for safety and hiking poles. Normally i just hand hold by tripod foot, but I'll be hiking for 5 days in Finland for many hours a day but with mission to spot various wildlife.Something that could attach to backpack straps? I have think tank lens changer but it only fits lens, with camera protruding. Also no way to attach it to anything but their huge belt...Is there some sort of bib maybe?Thank you... via /r/photography https://ift.tt/2Mz3TJh