I am new to Pathfinder and am building a Half-Orc Druid.
Favored Class Options
The following options are available to all half-orcs who have the listed favored class, and unless otherwise stated, the bonus applies each time you select the class reward.
Druid: Add +1/3 to the druid's natural armor bonus when using wild shape.
I do not understand how to interpret the "+1/3" text. There are two values separated by a slash. I assume the slash represents a condition. If so, what is this condition?
Furthermore, if I chose this bonus each time I selected the class reward, how would it accumulate on my AC?