A common situation to refer to this metaphor is when talking about the daily scrum meeting. Pigs are encouraged to contribute to the meeting because they need to collaborate in order to achieve the common goal and will be held accountable in case it's not reached. Stakeholders however are asked to be silent if they happen to attend the meeting.
Another classic situation is when talking about estimations. Estimations must only be provided by the the developers who actually perform the work and will be held accountable if the estimations are not correct.
guarantee the project is delivered as efficiently as possible. Chickens often provide guidance to assure that right job is being done and that the copmpleted job will provide value.