Excellent composition. I like how, despite the energizing colour red is the main one, there is a real since of peace and quiet, though in a farm yard there is always a possibility of some life, big or small, popping out from somewhere. Very skillfully painted.
You talked about an isolation coat between an acrylic ground and oils. That makes sense to me as from what I've read. Acrylics make a poor ground for oils due to them being too smooth as they form a closed layer. There is no chemical bond between acrylic and oil, so tooth is needed for a mechanical bond.
Critiques and comments are always welcome.