Many nouns can be used as both countable (C) and non-countable (NC) nouns depending on the context. A particular instance of a noun will give it the countable meaning.

Paper:
I read two papers every morning (C)
We need some paper to write on (NC)
Experience:
They had some bad experiences on their trip. (C)
He needs more experience for that job (NC)
Chicken:
They raise chickens on the farm (C)
We would like to order chicken for dinner (NC)