You are still thrashing about a bit, uncomfortably neighing at all the unfamiliar sensations: flexible ears, a tail, digits numbed into hooves...then she says:"I suppose I can let you graze while I won't be needing you. I'm sure you can't escape; and in the highly unlikely event that you do, I'll make a few more changes. So I advise you don't." As she presses a button, you can hear a creaking door go open behind you, providing a back exit into some sort of small grazing field with wooden pole fences demarcating it. You experimentally take a few first steps, producing a clicking sound as your hooves touch the stone floor of the stable, then a more shuffling sound as you step out onto the grass. Everything smells and looks new, your olfactory senses sharpened and your view now far wider than your human eyes allowed - even though it's in black and white. Instinctually, you carefully move your head down to the grass and begin grazing, picking it off the ground bit by bit with your tongue and lips. Contrary to your expectations, it tastes quite good.
You begin exploring your surroundings once your done. You tap at the rickety wooden fence with a hoof, producing a hollow sound. Could probably ram it over with a bit of effort or even jump over it as it's not too tall. However, you fear the lady's warnings of what she may do to you if you abuse her trust. Then again, she isn't around to see...is she?