The phrase "a bunch of crock" is likely a variation of the more common expression "a load of crock" or "a bunch of crockery," which is a colloquial way of saying something is nonsense or not true. The word "crock" in this context is used to refer to something that is deceitful, ridiculous, or just plain false.
The expression is used to dismiss or express disbelief in something that someone is saying or claiming. For example, if someone tells you an outlandish story or makes a dubious claim, you might respond by saying, "That's a bunch of crock!" Essentially, it's an informal way of calling out what you believe to be untrue or unfounded information.