We have had the exact same experience this week!
We just switched ordering from Chewy to Amazon (a little cheaper). Opened the bag, and it was a totally different product than what we have fed our dog for the past 8 years. The same bag and Wellness variety, just a different product.
The kibble is as described by the user above: maybe 3x the size, kernel-shaped vs. round, dark brown vs. tan, and has a very mild petroleum smell.
Throwing it away and headed to Pet Smart to buy a legit bag, and then back to Chewy.
