You have tried barriers and home-remedy repellants but you havn't gone after the problem with a professional solution. Chicken wire is too course by the way, the squirrils can go through it. You are on the right track, but you need to get some 1/4" hardware cloth.
For me, squirrels think twice or longer before decending out of their safe oak tree
and being introduced to the dogs. But, if a barrier doesn't keep them out, then you may need to resort to poison or trapping. I don't like rodenticides because I wouldn't want the mess.
That leaves live or dead trapping. When ever I need to deal with a pest I start by looking on www.bugspray.com. Strange name, but they have articles on every pest problem I have ever run across. So I learn what to do and then buy one or more of their products or and equivalent elsewhere. They have trapping products.
The other solution you havn't tried is an exterminator. Most of these guys guarantee their results and will relieve you of any association with the dirty deed.