## 1 Introduction  
Since the ban on conventional cages for laying hens in the EU in 2012 [1], alternative husbandry systems offering the hens more space and additional free-range areas have increased in popularity. In 2020, 20% of laying hens in Germany were kept in conventional free-range systems, and 12% in organic systems, both of which offer a mandatory free-range area attached to the henhouse [2, 3]. For German laying hen farms with access to a free-range area, it is regulated by law that a winter garden (WG) must be installed between the henhouse and the free-range area [4]. This area is defined as an additional part of the building with outdoor climate conditions and a littered floor. Moreover, natural light and, where necessary, artificial illumination is required [5]. In organic farms, the WG can only be counted to the usable surface per hen if it is accessible 24 h per day [6]. Hence, the WG may provide additional space and is suitable for performing species-specific behavior, such as foraging, scratching, and dustbathing. The offer of additional space, especially an outdoor run, is a well-suited option to prevent welfare problems in commercial laying hen husbandry. Flocks with access to a free-range area or a WG (or both) show less severe feather pecking behavior than conspecifics kept exclusively indoors [7]. Moreover, birds using the outdoor run more frequently show less feather pecking behavior [8,9]. However, not all hens use the additional outdoor area. A review by [PERSON] et al. [10] of 14 scientific papers researching range-use found rates of hens in the free-range area ranging between 9% and 70.5%, depending on the different methodology used. A WG may serve as a transit zone as it resembles the henhouse and introduces the hens to the outdoor conditions. Therefore, the WG could ease the transition to the free-range area. [PERSON] et al. [11] reported between 38% and 54% of a flock using the offered WG and staying outside for an average of 1:29 h to 2:20 h per day. In another study, up to 90% of 257 hens visited the WG at least once per day [12]. Thus, even the exclusive offer of a WG can motivate the hens to go outside. Moreover, a WG can enrich the laying hens' environment by offering additional enrichment material. Nevertheless, even in those husbandry systems perceived as animal friendly, behavioral disorders occur, such as feather pecking and cannibalism [13,14]. In addition to welfare aspects, increasing illness and mortality rates [15], as well as lower egg production rates [16] and increased feed intake [17] can also result from these behavioral problems and causing economic losses for the farmer. The occurrence of severe feather pecking resulting in plumage damage and injuries is higher in flocks with untrimmed beaks than in those with trimmed beaks [7,18]. Since beak-trimming in laying hens was abolished in Germany in 2017, the demand for measures that increase hens' welfare remains high [19]. The reasons and the likelihood of developing behavioral disorders are multifactorial. Not being able to perform behaviors that animals have a high motivation for causes stress [20]. Feed and husbandry and management conditions (e.g., the lack of dustbathing and foraging material) are further influencing factors [16,21,22]. Hence, developing feather pecking and cannibalism can be seen as misdirected exploratory or foraging behavior [23,24] and as a strategy to cope with stress and fear [25,26]. Different approaches for the reduction of these behavioral disorders exist. One approach focuses on animals that are better adapted to the environment in husbandry systems. Genetic differences also contribute to developing feather pecking under husbandry conditions [27]. Another approach is to improve the animals' environment. In addition to demand-orientated feeding [28], environmental enrichment plays an important role in these efforts [29]. A basic requirement in an enriched environment is offering an adequate amount of dry and scrapable litter, which fulfills the hens' need for dustbathing [30].