Or so it is defined in various 19th century glossaries of the Shetland and Orkney dialects. Note the pronunciation, reflected in the alternate spelling of oagarhinnse. A secondary meaning is an animal in poor (frightful) condition, rather than one frightful in itself but that's not the one that gets reported. Personally, I object to calling bats ogerhunches -- they adorable.
And wouldn't you know it, when taking out the trash I ran into a herd of hungry javelinas, the dammed ogerhunches.