The project "Legal systems and ethical values behind the official and the stakeholder-based animal welfare control" covers studies of farm animal welfare legislation and ten private animal welfare standards from four European countries. Their expressed aim of prevention of suffering is in focus. Many pieces of legislation stating the aim of preventing "unnecessary suffering" lack a clear distinction between "unnecessary" and "necessary" calling for definitions, as it is difficult to decide where to draw the line in actual farming, or for a citizen to interpret what is regarded acceptable by the legislator. Several interpretations are possible, e.g. the intensity and duration of the suffering, the intention behind the act, the fulfillment of human interests and the animals' interests. Furthermore, countries differ regarding what species are legally protected and at what level. We will further discuss ethical values behind such differences. Painful management procedures are legal in many countries, and hence regarded as "necessary suffering" in some –but not all – countries. As private standards are developed to meet consumer demands for a stricter interpretation of "unnecessary" it is important to clarify inherent values. We tentatively argue that besides utilitarian ethical thinking duty, contractarian and/or virtue ethical thinking can be found in both legislation and private standards. If so, this mirrors consumer interest in an integrated and complex reasoning related to the concept of "unnecessary suffering", a complexity that needs to be considered in forthcoming legislation.