Bed bugs can go for ages without feeding; the only real way to kill them en masse is extreme heat—e.g. the dryer. There are services that come and seal your house up and then essentially pump 125F heat into it, to kill the bedbugs (bugs @ 120F, eggs @ 125F). If suppose if your shed gets to ~125F in the summer, should be good. Point being: heat > time-since-last-meal for bedbugs. (unfortunately I am speaking from experience)

Edit/addendum: The bed-bug-sniffing-dog, while a very good boy, is a total scam.