.In predator/prey relationships, as just discussed with the grass and deer are all
prey producers?

No, only plants are producers because they can create their own food. (Glucose)

Explanation:

Producers are organisms that create their own food using photosynthesis such as plants, however not all prey are producers. For example if the predator/prey relationship is a wolf and a rabbit then the rabbit is not a producer because it doesn't make its own food.

I Hope this helps! Tell me if you have any more questions about the subject.