[member=467]sabrina[/member] - I don't think one should be diluting the salt and vinegar in water. (If one was using industrial strength acetic acid, then maybe, but culinary vinegar is only about pH 4 I believe.) Just dissolve the salt in the vinegar. I can't imagine a bit of salt and household vinegar is going to upset chickens and pets.
Flame guns are good, albeit there is an environmental impact from burning butane. (I have no idea about herbicides v butane in terms of relative environmental impact !) I do have a burner (roofer's version rather than a small "gardener's" version) - very effective at clearing top-growth, but obviously does not kill the roots and perniscious weeds will need repeat treatments as they re-emerge.
[Not the same problem, but I would offer a note about flame guns and field fencing: unfortunately, I have found to my cost, they can "burn off" the galvanising to fencing mesh/wires. Mine was rabbit mesh, but I imagine the wires of stock mesh would be equally affected.
I have also found to my cost that even my puniest strimmer will easily rip through rabbit mesh and, so, both burning and strimming along my fence-lines is now a no-no for me. I'm still pondering how best to manage fence-line grass and weeds.]