Never done it with foxes, but some common sense applies here.
When trapping a chicken stealer, its best to use a serious trap and the bait he wants - chicken.
When I say serious I mean just that. Decide what your level of responsibility will be in all of this.
Do you want to "re-home" the fox or dispatch it?
Dispatch is the ultimate answer to your problem - "rehoming" it sends the problem to someone else.... and maybe back to you one day, in spades.
Normally, a serious trap will be the leg trap or snare. No, these are not "humane," but they are designed for those who want to eliminate the predator, not be nice to them.
To use them, find the path it uses to enter the area and look for where the trail narrows to a natural funnel point. Hang the bait over the trap, in this funnel point. This way, it has to look up and reach for it. This diverts attention away from the trap zone, making for a better chance it won't see the trap and will essentially, stumble into it while reaching for the bait.
If you are using a humane trap live a Hav-A-Hart, just follow the directions that come with it.
Place the trap in the funnel point you've selected, so the fox is most likely to enter the trap - if he will. The phrase, "Sly like a fox" exists for a good reason.
If you catch him, swing into action on your exit strategy. Take him wherever you plan to discharge him immediately, or call in your benevolent government agents to dispatch him if you cannot.
Whatever you do, wear thick gloves, handle the trap and it's new resident carefully and keep your fingers away from the mesh. Foxes stop being cute when they are trapped. It will be scared, hungry and maybe worse - odds are good he will bite the "beegeebus" out of you if given the chance.
If you are releasing him, well... stay above and out of the way as you do.
Don't be sorry for him or try to make him your friend, either. It's likely he, or his kin, will be back.
