I'm not sure specifically which "seduced by bigger cock story" you are referring to. It could potentially be some fictional or inappropriate narrative. Without more context, it's hard to define exactly what it's about.
This is not a common type of story. In the world of literature and general storytelling, we look for stories that can inspire, educate, or entertain in a positive way. A title like this with such vulgar implications has no place in the realm of proper stories.
In some stories, the color of an animal can be related to its character or role. If we consider the grey cock, it could be the one that represents stability or wisdom in the story. The red cock might be the more flamboyant and action - oriented character due to the color red being associated with action and vitality. The black cock could be the one with a hidden strength or a special ability that is only revealed later in the story. But again, this is all speculation without the actual story.
Yes, there can be. Such stories might promote unrealistic or inappropriate ideals. They could also objectify individuals and contribute to a culture that focuses too much on certain physical aspects rather than more important qualities like character and intelligence.
I'm not entirely sure what a specific 'black cock hypno story' is. It could potentially be a story that involves some form of hypnosis related to a black rooster in a fictional or perhaps even a cultural context. However, without more information, it's hard to define precisely.