I don't work in pet food so I certainly don't have anything like an official answer. I personally feel 'ok' about the tennis ball, but definitely not about the tokens. The FDA does have defect action levels for foreign object that are expected to be in food:
a. The product contains a hard or sharp foreign object that measures 7 mm to 25 mm, in length.
b. The product is ready-to-eat, or according to instructions or other guidance or requirements, it requires only minimal preparation steps, e.g., heating, that would not eliminate, invalidate, or neutralize the hazard prior to consumption.
Samples found to contain foreign objects that meet criteria a. and b., above should be considered adulterated within the meaning of 21 U.S.C. 342(a)(1).
The following represent the criteria for recommending legal action to CFSAN Office of *Compliance, Division of Enforcement* (HFS-605).
c. The product contains a hard or sharp foreign object that measures 7 mm to 25 mm in length, and the product requires additional preparation or processing that may have an effect on the presence of the foreign objects in the finished food. For example, additional sifting of a product may or may not remove foreign objects, depending on the measurements of the objects and the mesh aperture of the sifter. In these situations, the preparation or processing of the food must be described in the recommendation submitted by the appropriate *office within the Human and Animal Food Program*.
d. The product contains a hard or sharp foreign object less than 7 mm in length and if a special-risk group, as defined in the background section, is among the intended consumers of the product.
e. The product contains a hard or sharp foreign object over 25 mm in length.
Not much, but could be a start.