The hogs appear to be digging for something other than peyote.

    Do not confuse this digging with the human holes encountered in Mexico. The two are usually easy to tell apart.
    Hogs dig with hooves from under the scrub brush and target something typically in or under the nurse plant roots whereas humans trample the nurse plants and use tools for digging out the peyotes.

    We have set up a game camera but presently lack a photograph of the hogs.
    However, this hog scat that we encountered on 8 March 2010 provided even more tangible physical evidence of their presence than did their holes.
    Two hogs were glimpsed on the run not far from the study site on our July 2010 visit.

    To learn more about feral hogs visit the Texas Parks & Wildlife Department website and download "The Feral Hog in Texas" PDF.

We have not yet captured images of the hogs we've seen but this http://www.youtube.com video depicts the problem nicely.