You weigh your options. You really needed to find someone else, but there was no way you were going to escape while Curtis was in the yard. He'd just turn your legs into fins before you could get anywhere, or turn you into a newt and trap you in a shoebox, or anything similar. There were many possibilities of failure, and you couldn't think of anything that could stop him before he mentioned a harmless animal. He's also threatened to keep changing you if you don't get in the coop, and while you hate this mutant form, it can still at least walk around. You resolve to escape when things are more stacked in your favor.
You awkwardly shuffle to rotate yourself toward the coop. Your feet were thankfully wide enough to keep you upright in spite of the large udder hanging off your gut, but you still hadn't grown accustomed to the weight it has added to your frame. Each comically-wide step you take is accompanied by your udder swaying and pressing into your legs. As you pass into the coop, your blood freezes for a moment as your udder pressed into the cold bar that framed the coop's door. You hadn't considered how much more you were carrying in front.
As you get into the coop, you try to sit, but your udder reaches the floor before your rear does. You instinctively attempt to move back so the udder gets moved less, but you instead push yourself into the back fence of the coop. You give an annoyed cluck, and look to Curtis. He apparently found your actions funny, judging by the punchable grin he was giving you. You cluck a bit, and point to your udder with as expectant a face you can muster, given your current condition.
"Good job! As a reward, I think I'll milk you!" Curtis approached the coop's door, then closes it. "...Right after I get back from work! It seems like emptying you out now is just tempting fate, assuming you've actually got milk in there. Maybe you've just got a big cow udder!"
You blanch as your udder gives off a familiar pressure. The pink extending from your gut pulses further outward and your teats engorge with newfound growth. You heave yourself into a standing position, but as your udder continues to swell, your legs begin to give out, pulling you back to the floor. You reach out with your hooved limbs as milk once again fills the space made, but now the udder's teats are far enough that you need to curl your upper body over it to reach them with your stubby arms. In a matter of moments, your udder settles again, notably larger than before, and still begging for release.
Worse yet, it appears Curtis noticed your changes. "Interesting! I was wondering if I could change the size of some of my additions." You struggle in place, trying to figure out how to carry your new weight. Curtis gives you a disgusting stare, more like he was grading meat than looking at another person. "Perfect! I'll be back in about 8 hours." He turns around, ignoring your desperate clucking accompanied by the clanging of your cowbell. Just before he closes the door to his house, he looks to you with a sadistic smile. "Don't go anywhere."