Leaving aside related concepts that might stem from this conversation such as veganism or animal rights...The more I read Tanakh the more it seems to me that the Torah and Tanakh as a whole view animals as sentient beings. God open's up the Donkey's mouth, but scripture doesn't imply that God told the donkey what to say. The donkey instead takes the opportunity to air its personal grievances, and even discusses its long memory of being good to its master.
Nineveh is spared not just because of people, but because of the animals who live there. The psalms discuss how the animals cry to God for their food. The animals in the story of Noah seem to travel to the ark on their own, as if God told them to go there and they figured it out without needing to be rounded up. God sends ravens to feed Elijah, and it's spoken of in a matter of fact way and not in a overtly miraculous way. We can't forget the serpent in the garden of eden, who was described as the most wise of the animals, implying that animals were made with a capacity for wisdom. Proverbs discusses learning from ants and other animals. But even after Tanakh I've also noticed various midrashim that discuss speaking animals that argue and reason, such as Elijah's bull which didn't want to be sacrificed to Baal. Or a donkey sold to a non Jew that refused to work on the Sabbath. Or Rabbis talking about learning traits of holiness from animals. It seems like Judaism early on took for granted that animals possessed more sentience than what we see in later Jewish works.
As other's have answered, the Rambam is a pivotal figure in arguing that animals have emotion and imagination but he also argues that animals have no intellect or reasoning abilities. This argument seems to be counter not only to Tanakh and Talmudic sayings, but also to modern science which shows without a doubt that animals can reason, plan ahead, and build compound tools.
So does Judaism have a core concept of animals being sentient (not just emotional) beings? And if so, where is this discussed?