What kind of feathers are on Curley's wife shoes?
When Curley's wife appears in the barn where Lennie is sitting and thinking about the consequences of the puppy's death, she is wearing mules decorated with red ostrich feathers. These shoes would not have come cheap, because ostrich feathers in that part of the world would have been expensive and difficult to come by. Ostrich feathers would have made the shoes look particularly glamorous.
These shoes therefore reinforce the socioeconomic and cultural divides between Lennie and Curley's wife. Thanks to her marriage to Curley, she has access to resources and luxuries that Lennie is unlikely to ever have.
The shoes also seem to fit with Curley's wife's reputation of being flirtatious. These shoes were clearly designed to make herself stand out and be noticed.
Ostrich feathers. The notation is in Chapter Five.
Ostrich feathers. And the shoe style was someting called "mule."
Wikipedia: "Mule, a French word, is a style of shoe that is backless and often closed-toed. Mules can be any heel height - from flat to high. The style is predominantly (but not exclusively) worn by women.
From OMM, p.26....
[[Both men (George and Lennie) glanced up, for the rectangle of sunshine in the doorway was cut off. A girl was standing there looking in. She had full, rouged lips and wide-spaced eyes, heavily made up. Her fingernails were red. Her hair hung in little rolled clusters, like sausages. She wore a cotton house dress and red mules, on the insteps of which were little bouquets of red ostrich feathers. "I'm lookin' for Curley," she said. Her voice had a nasal, brittle quality.]]