Afraid of turning into a donkey again, you immediately withdrew your head to check. You were relieved to find that the donkey bits weren't coming back - You even rubbed your ears to check. Aside from your lower jaws getting sore from all the chewing, you seemed to be in the clear. Your stomach rang its complaint again, prompting you to bury your face back in barrel to lap up some more oats.
You would bob your head up to occasionally to check for changes at first, but after coming up empty for the twentieth time you had practically thrown all caution to the winds and dunked your muzzle right in. Paying no heed to your steadily swelling belly or your aching jaws, you just kept eating and trying to fill your void of an appetite. It wasn't until half the barrel was gone did you clamped the lid back on with a content burp, amazed at its tastiness. You glanced down at yourself one last time to check that, yes, you weren't sprouting any hooves or tail - Your body still looked pretty normal, even sporting a slight pot belly that is standard for a healthy jack.
Having dealt with your hunger, you pondered on what to do next. Should you try to find some water to drink next? Or a nice place to bed in? Perhaps a fertile jenny to keep accompanied with...?
You blinked and shook those silly thoughts away. Right, you still need to escape first. Trying the doors proved to be futile, they were barred on the other side. You supposed that you could try and scale up the wall to the ventilation holes near the ceiling, or hide and wait until somebody opens the doors.