I finally figured that part out, PP. I am sorry I laughed, but the picture in my mind was just too funny. I had forgotten about barn cats until the mention of a feeder mouse.
I know the situation is not funny.
Do you think placing the cage just outside of the barn door might work ? The hawk may be attracted more to the sound of a prey animal in distress than to a hunk of meat it does not recognize as food.
Smiles,
Lyn