I create these images using natural light. No flash required. although I always have one with me. All I need is a stable door, barn entrance, doorway.
If you are struggling with a dark area, I do have a studio set up with a dark backdrop I can bring for the smaller animals or people.
If you would like a black portrait but not a full photoshoot, I can do these images with an A4 print from £35 within the LN4 and LN10 postcodes.