I absolutely love what you are doing here, and may have to try this crowd-sourcing idea sometime. How very clever!! I love the replies you are getting as well. There are some really interesting directions you can take with this story.

The dramatic tension at the beginning of the first chapter is spectacular. I guess I wouldn't advocate killing off the dad, as he is a remarkable character that we love to hate, and I would like to see that relationship played out. You can continue to build tension in future chapters if he remains alive.

What if the hole next swallows up Zoe and the sheep and they end up in an abandoned mine? They spend a week or more living on sheep until they can find their way out and Marcus has to face his father, with a lot of cuts and scrapes, fewer sheep and a (possibly pregnant) girlfriend?

I'm dying to know what it is about her that makes her known mostly as her father's daughter. What is the stigma there? Maybe it takes a few chapters to get to it. You can build on that. Is her father still alive? Is there some ancient feud between the two fathers?

Another really intriguing aspect of the story is that it's modern day, obviously (cell phones), but there's something off about it that as a reader I really want to learn about. Is it in a time when the economy has collapsed? The farming community is worth exploring. Perhaps they have had to subsist by trade as currency has no value any longer. What are the other farms and ranches in the area doing to survive? If there really is an abandoned mine beneath the cave, what was mined there, and is it something that could turn everything around for the community? Or maybe there is some terrible ancient secret as to why the mine was abandoned. It could be something supernatural, or something horrific that happened and that was covered up.

You have a terrific imagination and a wonderful writing style. I look forward to seeing where you go with this!