Adam had quite a few horses on his farm, namely Morgans. The horses that were bred here weren't built for fast racing like Thoroughbreds or heavy hauling like Clydesdales, but they were versatile horses that can be used in any task put to them. Plenty of fine farm horses came from this farm or were related to the horses here. In fact, today Adam and Evelyn were going the most prized breeding pair a full grooming session.
Once the grooming supplies, including the new shampoo, was gathered up, the horses in question were called into the barn. Daryl was a fine look stallion with a light chestnut coat and slightly darker mane while Daisy was a yellow mare with a blondish mane. The two of them were agreeable horses and seemed to look forward to their grooming. Adam led Daryl into his own stall while Evelyn took Daisy. After hosing down their respective horses, they started sudsing them up with the shampoo.
For a while, things were going relatively fine. The horses had collected quite a lot of dirt so that required much scrubbing. Evelyn had been scrubbing Daisy's chest to get all of the dirt off of it. She noticed that the chest felt a bit more plush than usual. Perhaps it was time to put Daisy on a diet. It seemed to be getting a little hotter in here as Evelyn wiped an arm over her brow. She stood up tall so she could scrub down Daisy's neck. It was then she noticed that Daisy didn't seem as tall as she remembered and her head looked...smaller? As Evelyn reached around to work on her mane, Daisy moved her head down and bumped into Evelyn's breasts. That gave Evelyn a jolt of surprise. Daisy bumped her rather hard and her breasts seemed a little more tender... She paused when she looked down at her button-up shirt. Her breasts had grown considerably bigger since they were this morning. Gaps were forming between the buttons as they pressed further forward. Evelyn couldn't believe they were getting so big and she hadn't noticed yet. She quickly undid the buttons, allowing her bigger breasts more room to grow. They looked read to tear her bra apart. But more noticeably, Evelyn could see the black hair that was starting to grow over them as well as a good part of her stomach. That hair was spreading out further as her jeans started to get tighter on her.
Meanwhile, Adam had been scrubbing down Daryl's front legs and noticed that his hooves looked like they were cracking. That didn't look good, Adam will have to call a vet if it looked like Daryl's hooves were breaking up. Oddly, his back hooves didn't seem to have any problem. Adam felt around the tough keratin, trying to find a nail or something that was wedged. He couldn't find any foreign object, but it felt like there were more bones than there should be in in the horse's forelegs. Just then, there was a small series of pops as the hooves broke into five even pieces. Adam was distraught for a moment until he saw that something was unfolding under the hoof fragments. The fragment seemed to shrink down as they adjust to fit at the end of the ends of the extension. The more it unfolded, the more it looked to Adam like a human hand. That's when Adam looked at his own hands. They were almost covered by a layer of dark brown hair and his fingernails had become thicker and darker, like a horse's hooves.
Adam quickly scrambled out of the stall, putting distance between him and the horse. Something very weird was happening to the two of them and Adam didn't want it to get worse. At around the same time, Evelyn staggered out of her stall, looking like she was walking with pain. Her boots seemed to fitting her very wrongly. Of course, that wasn't the only thing that wasn't fitting right on her. Her shirt had been opened to reveal a bra that was about to explode from the large black-haired breasts it was trying to contain and her jeans looked like they were splitting at the seams. Adam walked toward her, becoming increasingly aware that his own clothes were also becoming restrictive.
Evelyn looked at Adam, who was bulking up to the point where his clothes looked painted on. Adam wasn't a scrawny man with all his years of hard farm work, but his muscles were never that big. Evelyn couldn't help but notice the front of his pants were bulging to almost obscene size. Looking that Adam needed help, she tried to walk toward him, but had to sit on a hay bale as the pain in her feet became too much to bear. She pulled as hard as she could on her boots, wishing she had a big shoehorn to get them off faster. Slowly, she was able to slide the boots off her feet and when she looked at her bare feet, she felt queasy. Her toes seemed to shrank down to nothing as her toenails had melted into one hardened mass. The mass grew thicker, darker, and spread even further. Now it looked she had a pair of horse hooves for feet. She looked over at Adam and saw that his own boots have been pulled off to reveal a similar pair of hooves.
Evelyn slowly stood up, struggling to maintain her balance on her new hooves. She walked carefully over to Adam, her steps becoming more confident as she moved. She bent over to help him with his pants, which cause her own pants to rip apart completely. Which was just as well as her coccyx suddenly sprang out and extended before long black hair started growing from it. The grimace on Adam's face told her he had also just grown his own tail. But Evelyn was focusing on removing Adam's jeans and she pulled open his button and fly. This release gave his bulge even more room to grow, but before she could grab his underwear, it ripped apart as a horse cock sprang out. Evelyn's eyes bulged with surprise. It had to be 10 inches long at least and as thick as her wrist was. The balls under it have grown to match. Evelyn tugged harder at his jeans, tearing them apart. In a similar vein, Adam started pulling off what was left of Evelyn's clothes. His shirt was soon shredded apart, revealing heavily toned muscles.
As dark brown and black hair covered the rest of Adam and Evelyn's respective bodies. They winced as they felt the changes overtook their heads. Their necks extended a few inches before their ears started stretching and moving upwards. This paled in comparison of what was happening to their faces. Their faces distorted as everything started moving forwards. Their eyes were the first to stop traveling forward as they sank into newer positions. Their mouths and noses kept stretching until they formed new muzzles, more teeth sprouting from their gums.
When the changes seemed to stop, Adam stood up, still taller than Evelyn even if she had gotten taller herself. They were both now anthro horses, he a dark brown stallion and she a black mare. Adam's body was a perfect model of masculinity with every muscle chiseled in detail and his equipment were almost as large as a real horse's. Similarly, Evelyn's feminine beauty had also increased. Her breasts were large, round, and somehow defying gravity, probably because of her larger pectoral muscles. Her hips flared out widely and her ass was almost as larger as a real horse's, but much more shapely. As Adam and Evelyn were trying to make sense of it, she heard the sound of hoofsteps and looked to see Daryl and Daisy coming out of their stalls, also anthros.