Hi Ann and Ellen,
Ann, We have over a half acre in iris and it is broken up into three different areas on our 1 2/3rd acre. I don't think chicken wire would work. Ellen, I think the gophers are unaffected to any poison in the rhizomes. They have destroyed several iris so far this year and nearly wiped out one large section of our garden last year when Jim was so ill.
So hopefully, someone will have another suggestion. Oh, yes we have tried the traps, too.