Henry led David and Stella the jenny followed, down a darkening corridor to a lower level within the stable. The sounds and smell from above, David could tell there must be dozens of animals above them.
"Let me show you one of our fine box stalls for a moment," Henry said, motioning David through a wood and steel bar door.
David stepped in, a bit hesitant as he had never been in a horse stall before. A single lightbulb hung from the very high ceiling, and the only window in the room was on the door David had just stepped through. The air hung heavy around him, as there was little circulation. "No offense Henry, but this place stinks!"
Just then he saw Henry guide the jenny Stella into the room and slam the door shut. A sliding sound and thud signified that Henry had bolt locked him in with Stella.
"What the hell are you doing?!" David ran to the window and saw Henry standing there laughing. "Let me the fuck out of here damn it!" David banged on the door but it held solid.
"Hehe.. I don't think so David. Don't worry, you'll come to see I'm doing you a major favor quite soon."
David banged on the door again, "You god damn maniac, I'm calling the police when I get out of h...". David stopped beating the door when he noticed his arm seemed a bit darker than normal. He rubbed at his forearm and was shocked to find a thing layer of smooth hair across it. A quick check over the rest of his body revealed the same - his legs beneath his shorts and both arms had a light covering of fur, and even worse, it seemed to be thickening and growing. Just then David remembered that strange drink he was given earlier...
"What was in that drink?! What the hell's going on?" screaming and shaking his fist at Henry.
Henry chuckled as he turned to walk away, "Just take solace in knowing that in a short while you'll be having the time of your life David... most everyone who comes here, does..."
David barely heard what Henry had said before he left, he was too concerned about what was happening to him. Already he had broken into a frantic sweat, and as he lifted his shirt up in the front to glance at his belly, he was dismayed to find even more smooth hairs. Thickening around the back of his neck and a bush of it on his butt. Stretching his shorts open with a finger to glance down between his legs, only to find his member had grown strikingly erect - not only that, it too seemed to be darkening... and as he watched a leathery pouch of skin formed around it and attached itself to his belly, forming what looked to be a sheath. David shreaked and let his pants cover himself again, only now they felt much tighter.
David frantically glanced around the room, looking for a way to get out. He noticed Stella standing there in the corner of the room, her rear turned toward him, her tail swaying side to side. Why did Henry leave her in here with him? It was then that the sheer realization hit him. Henry had told him that he had just acquired a new male to mate with his jenny's and mares, and he had hired David to assist. What Henry had in fact meant was that David was to become the actual stud, and that he would be the actual one mating with the females!!!
David ran back to the door, although a little clumbsily - his body seemed larger and he felt unsteady on his feet - and shouted through the small window, "Let me out of heeeraaaaw!" David froze and put his hands - or what was looking to be forming hooves - to his mouth. Even his voice was changing now! Not only that, his face felt as if it was pushing outward.
His inspection of his face was interrupted by an abrupt pain in his feet as his shoes fought against the growth. David stumbled to the ground and tugged at his shoes, managing to pull one off. Though as he pulled at the other one with his growing hooves a quick rip at the end of the shoe and stretch of his foot exposed a shiny new hoof attached to the end of his rapidly lengthening foot.
David turned over and got on his hands and knees, his growing mass strecthing his clothing to the limit. He arched his back and let out a loud, "NIEEEEGH!" as the seat of his shorts blew out, revealing a bushey coarse haired tail.
The change made David feel very dizzy as his head lengthened and his muzzle pushed out. He tried to speak again, but all that came out was a loud whinny. He shook hid head, as if to shake off the change, his now equine ears flopped about.
His shirt ripped down the front and back, falling to the ground. The smooth coat of dun colored hair covering his entire body was enhanced by the black mane and his magestic tail.
David stumbled and tried to stand up again, knowing that he had to get out of that room somehow, but he couldn't get onto his back feet. He reared up and tottered uneasily on his back hooves, but then fell back forward again, his front hooves hitting the stall's dirt floor with a dull thud. He walked slowly to the door and tried to think how to knock it down...
It was then that he noticed something in the air.. somehow he knew that thick scent... it was that jenny..Stella, he could still remember her name. She smelled like a mare in heat, sota rank. David stared at her rear, the tail upturned to one side and willing. Her rear hooves spread out and firm in the ground... ready to take his advances.. a squirt of urine giving the air a thicker scent of wanted sensation, her vagina moist and ready, the pheromones pumping out...
Standing there his mind filled with male ego thoughts and stallion hormones pumping up his muscles, David was a stallion stud ready to meet the challange of being a stud!