Help! Fox!

Hi! My 3 fluffy babies live outside in a hutch with run permanently attavhed. The wire is standard square 2mm thick (at least) I'd secure on all sides and sits on a patio permanently. Since our dog passed recently, a fox has been visiting the garden and has discovered the bunnies. Now, normally i don't bother locking them in the hutch at night, so they have free access to the run (and spend all their time out there).They seem much happier this way. I've locked them in the hutch tonight, but they seem more freaked out being locked out of the run. Question is - is it better to stress them by locking them away, or leave them access to their run but have them freak out when the fox comes???

Sorry to hear of your unwanted visitor. A predator visiting can scare a rabbit to death literally or it would possibly hurt itself in a panic to get away so, yes, I think you are right to lock them away. Unless the wire is 19g galvanised and doubled it is still possible for a determined fox to get in. They can also try gnawing through the hutch wood, lift the run if its not secured to the floor and can open the twist catches so padlocks are a must.
Immediate deterrents are security light and male human pee around the garden. There are a lot of posts on deterrents if you do a search with ideas that may help.
Sorry to be so negative but now foxy loxy knows they are there he will return often. Hope your buns stay safe.