What did the farmer say to the horse when he walked in the barn?

Short Answer: "Hay there, long face! Ready to hoof it?"

Explanation: The farmer's greeting to the horse plays on the word "hay," which sounds similar to "hey." The phrase "long face" is a pun referencing the horse's literal long face, but also implies that the horse might be feeling a bit down. The farmer's question about being ready to "hoof it" adds a playful tone, as it means being prepared to walk or run. The use of the 😄 emoji emphasizes the cheerful and lighthearted nature of the interaction.