Reinforcing fibers made for concrete work for stucco, too.
Here we're using Fiberstrand made by Euclid chemicals.
These fibers do reduce the cracks, but have other benefits. Hairy mortar bonds better to successive coats. Also, flexural strength is improved.
For years, animal hair was used in plaster, as well as lime basecoats, and portland basecoats. The use of reinforcing fibers dates back to the ancient egyptians.
Up until the early fifties, hair was bought by plasterers at farmer's markets and building supplies. When farmers butchered animals such as pigs, they would shave them. They would then save up the hair and sell it when they went into town.
These days, animal hair would probably considered a hazardous material, unless it was sterilized.
These modern fibers are made from polypropylene, and are cheap. We make 6 bags of portland with a two lb. bag of fibers.
The expensive part of using the fibers is they must be dry mixed in the mortar
by hand. In a mortar mixer they clump up.
The fibers do a lot of good.