In recent decades, housing systems with open construction or in which functional areas and
resources are relocated from a closed barn area to outdoor areas have been increasingly
developed and used, particularly in organic farming. They may offer advantages in terms of
various aspects of animal welfare, including improved air quality, greater opportunity to
experience climate stimuli and additional stimuli (e.g. visual or olfactory) and choice between
different microclimate areas. The new housing systems often do not allow a clear distinction
between indoor and outdoor area due to their open construction. Some of these housing systems
can (depending on the design) be formally classified as non-compliant with Regulation (EU)
2020/464 in terms of indoor space allowances, particularly, although they fulfil or exceed the
total space requirements per animal. It is therefore the question whether or not such systems
should be allowed in order to promote high animal welfare standards in organic husbandry. For
cattle and pig housing systems, welfare criteria were derived from the relevant animal needs,
based on an extensive literature search. Possible challenges animals are exposed to in these
systems were taken account of, for instance regarding thermoregulation and effects of
precipitation. The criteria were exemplarily applied to selected examples that are currently
critical regarding compliance with Regulation (EU) 2020/464, involving discussions with a
broad number of experts. On this basis we propose that for the new more open systems the
differentiation between indoor and outdoor areas is less meaningful, and instead the developed
criteria should be applied to evaluate whether these systems may contribute to high animal
welfare standards. If that is the case, a derogation from Chapter II Section 1 Article 3 and
Section 3 Article 10 of Regulation (EU) 2020/464 should be possible, allowing to deviate from
the minimum indoor or outdoor areas required in Part I of Annex I under the condition that
these innovative animal welfare-friendly systems provide the minimum total area (indoor plus
outdoor area) required.