Going to duct tape hands about having dogs off leash.
Marli, there are many problems with flexi leads including a dog too far from you should another animal charge. Work on loose leash walking so the dog doesn't pull and husband doesn't feel need to use one.
http://www.clickerlessons.com/looseleash.htm
That said, squirrels and chipmunks. Mine lose their minds when they see them. I use a leash they can't bite because Arwen would almost chew her legs off to get to one, but has learned the basenji proof lead won't give. Thanks to Jack Austin for telling me how to make one!