If you imagine your requirements as a stack of index cards, you tell development about those that are ready to be worked on. Always have a prioritized stack of cards so you can instantly fulfill their request for something to work on. But when it's time to lay out a release, give them a small portion, enough to keep 'em busy, and then give 'em more when  they're ready. Work on the mowing requirements, then the snow plow requirements, then the trailer requirements. We don't want them to cherry-pick through the "best" requirements and give you a bunch of disconnected features.

You SHOULD be able to have an adult conversation on requirements with your dev leaders that includes "I'm not ready for you to work on this but I'd like to discuss it."

Answered by Steve Johnson