Question

Can a fable have gods that are directly involved with the plot of the story?
Are all fables really short and not descriptive?

Fable:
A short moral story, often with supernatural or animal characters.

http://www.onelook.com/?w=fable&ls=a

Remember in the Old Testament when God made the donkey talk? Was that story short, and did it have a moral lesson? Was there a God or animal involved?

http://www.newlivingtranslation.com/05discoverthenlt/ssresults.asp?txtSearchString=Numbers+22%3A1-35&find.x=0&find.y=0

I hope this answered your question. I personally love fables, it lets me lie a little, and still deliver a great moral lesson.