Off the top of my head, I was surveying some woods around Lincoln a few years ago, on a test site with some surface and buried pigs that were placed there several years ago. Whilst there was no surface evidence (i.e bones), once I looked at the geophysical data, there were some clear anomalies where the surface pigs used to be. It turned out the pig fluids were retained in the soil and this is what I was picking up, very weird!
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