There are several pet stores along Chestnut Street, including a pet supply store near the eastern end and K9 Health & Supplies all the way at the western end. Rittenhouse Square Pet Supply sits a few blocks below Chestnut Street. In case of emergency, the Center City Veterinary Hospital and O'Neal Animal Hospital are at opposite ends of the street.
You'll find small patches of grass along your walk, but as this is one long city sidewalk, don't expect a lot of natural foliage. You'll be walking on concrete sidewalks along a busy, multi-lane, one-way road. Exercise caution because parts of Chestnut Street can become very crowded, especially near Independence Hall during high tourist seasons.
If you want to avoid tourists, there are many other parks to enjoy at the other end of Chestnut Street. You can easily access the Schuylkill Banks from Chestnut Street for a peaceful walk along the river. Near the University of Pennsylvania, you'll find Hill Square, a grassy area with several walking paths.