That's rough bro ... If the majority of the vegetation was eaten, then there's a very good chance they will be so stressed from that & hermie on ya n hit ya with seeds & pollen. It's worth a try tho if this is all you're working with and it's not too much work for ya. Try to fence or gate them any way you can to prevent that in the future, and if they do herm out on you just let it produce as many trichomes as possible and then use the buds/trim to make hash or butter/oil. That way you can atleast take whatever thc it does produce, and convert it into a more potent & enjoyable substance! =)
Best of luck to ya, on this grow, and next time around!