I cannot recall the title or the author; the premise was that, in an heavily over-populated world, scientists developed a new herd animal which was easily bred, matured quickly, and 100% of the creature was edible, high in protein and low in fat. As near as I can recall, the animal had several different genetic strains, including cow, pig, and dog. SPOILER ALERT - the twist near the end involves the animals developing high intelligence, the power of speech, and reasoning capability, raising the moral dilemma about creating and slaughtering one conscious species to feed another. Any idea?
This must be Mike Resnick's "Old MacDonald had a farm", published in September 2001 issue of Asimov's.
Matching from @mimi-joyce description:
- a new herd animal which was easily bred, matured quickly, and 100% of the creature was edible, high in protein and low in fat.
"Caesar MacDonald’s masterpiece was the Butterball, a meat animal that matured at six months of age and could reproduce at eight months, with a four-week gestation period. It weighed four hundred pounds at maturity, and every portion of its body could be consumed by Earth’s starving masses, even the bones. "
- the animals developing high intelligence, the power of speech, and reasoning capability, raising the moral dilemma about creating and slaughtering one conscious species to feed another.
"Don’t be that sure," said Julie, who had joined us while I was talking to Cotter. She had an odd expression on her face, like someone who’s just undergone a religious experience and wishes she hadn’t. "Mine looked at me with those soft brown eyes and asked me, very gently and very shyly, not to eat it." I thought Cotter would shit in his expensive suit. "That’s impossible!" "The hell it is!" she shot back. "They are not sentient," he said stubbornly. "They are mimics. They do not think. They do not know what they are saying." He stared at her. "Are you sure he didn’t say ‘feed’? It sounds a lot like ‘eat.’ You’ve got to be mistaken." It made sense. I hoped he was right. " ‘Don’t feed me?’ " repeated Julie. "The only un-hungry Butterball on the farm?" "Some of them speak better than others. He could have been clearing his throat, or trying to say something that came out wrong. I’ve even come across one that stutters." It occurred to me that Cotter was trying as hard to convince himself as he was to convince her. "We’ve tested them a hundred different ways. They’re not sentient. They’re not!"
A link to the full text, via The Internet Archive: Old MacDonald Had a Farm by Mike Resnick
This sounds like a mix of Isaac Asimov stories:
A Statue for Father is a short story where a man becomes known for bringing dinosaur eggs to the future, which turn into a vast source of extremely delicious food for a growing population; the twist is, he's not remembered for inventing time travel but for inventing dynachicken. This sounds like your food source, but dino's don't become intelligent, so maybe not.
I remember there was another short story I read in a collection (pretty sure it's Asimov) where an alien race comes to Earth to apologize; for centuries they had hunted humans for food, and it was very difficult for them to accept humans as intelligent creatures. The humans they interact with make them feel miserable about it, to the aliens decide to teach humans a lesson; as they leave they modify pigs to become intelligent, putting humans in the same spot the aliens find themselves in. But I can't find the title of this one to save my life.
Does that sound close to what you're looking for?