Your original sentences are mostly correct but can be improved slightly for clarity and punctuation. Here's the corrected version:
A snail is the slowest animal on land. And why hurry if your home is always on your back?
Explanation:
- It's better to combine the second and third sentences into one question for smoother flow.
- The question mark is placed at the end of the combined question.
- The sentences are clear, simple, and grammatically correct after this adjustment.