TTG-
They are "traction chains" not only what a lot of people think of as "snow chains". I have heard that they can dig you into mud faster than plain tires, but I would not be a bit surprised if tires alone would have come to the same result. I have heard that they can help a LOT in mud, but of course they are not invincible. Extremely soupy mud will be different that just wet mud. I've used them in mixed snow and ice and mud, effectively.
If you have the machinery on-site to pull trucks out if they get stuck, you would only lose maybe 30 minutes by putting on the chains, but might gain a lot of time/ wear and tear saved. I say its worth a try.