DJT wrote:to get scale have you considered PSing a cow
I've heard that New Zealanders often carry inflatable sheep for such situations
Norm, it's going to be difficult to get a sense of scale shooting with a 300mm as the perspective will be fairly 'flat', even if you get down low. Getting in close and low with a wide-angle will give an impression of height, but even that might not help much in showing the largeness of the bales. I know you said you didn't want anyone in the pic but I think that an 'ambiguous' figure would have helped with the scale without taking away from the image. Maybe someone partially hidden behind the left stack of bales or in the deep shadows on the right, maybe slumped down with a hat across their face as if they have just spent a hard day in the field.
I like drop-shadow frames, but I don't think they work very well with text, particularly if the text extends into the shadow area. As you have some 'empty' space at the bottom of the image, an option here might be to include the text over the bottom of the road and then use a drop-shadow as well (although you might need to alter the text colour).
Regarding shadow size, my rule-of-thumb is that the white outer border (blank canvas) is at least as wide again as the shadow part. (In other words, the shadow only comes half-way across the blank white canvas part.
The revised text colour is good - generally if you pick a tone from the image it will work well, and it doesn't need to be the dominant colour.