That and a river only flows one direction. The only reason he woudlnt have followed the river to a walk out point is it flows further away from the farm or it is all canyon (which makes no sense given the location) or a waterfall is in the path.
Before you argue this, keep in mind I was a CDF fire fighter for a couple years and have been on many a search and rescue operation in rain, floods, snow, heat, fire and goat feed for a large group of goats that somehow made their own way to the basement of a semi burnt out home to escape a large forest fire. Talk about a major "WTF!" moment with all these devil eyes reflecting at you not knowing what your looking at...