Those Sheep are contaminated.
You NEED to be concerned about the odor/smell being emitted from sewage. Odor means that the material has destabilized and is still putrefying, emitting endotoxins and other harmful bio-aerosols and pathogens
Processed Sewage Sludge (Biosolids) contains a vast array of toxic and persistent chemicals most of which are neither monitored nor regulated.

Sewage sludge of any class is such a complex and unpredictable mixture of pathogens and chemical compounds that even if all the constituents were known, it would still be impossible to reliably assess the health risks if and when this toxic waste is land applied.

Read the EPA Office of Inspector General's Report No. 14-P-0363.

By the way for the ignorant tree farmer, the municipality has made you a sucker.