## 3 Results
### Use of the Winter Gardens  
The inter-observer reliability (calculated using [PERSON]'s alpha) was 0.99 for hens per m\({}^{2}\) and 0.93 for hens per PP. Intra-observer reliability from 11 months apart was 0.995 for hens per m\({}^{2}\) and 0.93 for hens per PP. Following [PERSON] and [PERSON]'s [40] classification, the agreement between the observers can be rated as almost perfect.  
The results showed a significant influence (\(p<0.05\)) of the factors \"phase\", \"WG\" and \"Time of day\" as well as their interactions on the number of animals per m\({}^{2}\).  
The number of hens recorded in the WGs differed significantly between the four WGs and during the phases (Table 2). Over the whole housing period, on average, 1.48 hens/m\({}^{2}\) (SD: 0.88 hens/m\({}^{2}\)) were detected in the control WG (WG 1 without automatic enrichmentdevice). Significantly more hens (\(p<0.05\)) were counted in WG 3 (2.59 hens/m2, SD: 1.53 hens/m2) with a single enrichment device and WG 2 (2.43 hens/m2, SD: 1.27 hens/m2), where the doubled amount of PPs was offered. In WG 4, where the device was also installed single, on average, 1.79 hens/m2 (SD: 1.43 hens/m2) were counted, significantly less (\(p<0.05\)) than in WG 2 and WG 3.  
Among the different phases, the average number of hens per m2 in WGs 1-4 remained much the same until the end of the laying period, when it was significantly lower (\(p<0.05\)) than in the phases before. Except WG 4, most hens per m2 were counted in phase C. In WG 4, the highest number of animals occurred in phase A.  
The lowest use of the WGs was recorded in WG 1 during the peak of lay with on average 1.24 hens/m2 (SD: 0.9 hens/m2), while the highest use was recorded in WG 3 during the middle of lay with on average 3.2 hens/m2 (SD: 1.83 hens/m2). Figure 2 shows the number of hens per m2 in each WG during the four phases.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Phase**} & \multirow{2}{*}{**Mean (SD)**} & **Hens/m2** & **Hens/m2** & **Hens/m2** & **Hens/m2** \\  & & **WG 1** & **WG 2** & **WG 3** & **WG 4** & **WG 1-4** \\ \hline A & 1.45 (0.9)  & 2.54 (1.63)  \\ B & 1.24 (0.9)  & 2.21 (1.52)  & 2.05 (1.5)  & 2.92 (0.93)  & 1.62 (1.42)  \\ D & 1.24 (0.8)  & / & 1.29 (0.94)  \\ \hline A-D & 1.48 (0.88) & 2.43 (1.27) & 2.59 (1.53) & 1.79 (1.43) & / \\ \hline \hline \end{tabular}
\end{table}
Table 2: Mean (Standard deviation) number of hens per m2 in the four winter gardens (WGs 1-4; WG 1: Control, WG 2: double offer of the enrichment device, WG 3 and WG 4: single offer of the enrichment device) and housing phases (A: beginning of lay LW 23/24, B: peak of lay LW 32, C: middle of lay LW 40/41/51, D: end of lay LW 63/71).  
Figure 2: Boxplots (data range, median, lower upper quartile; outliers are included in the graph as dots and means as a cross) showing the number of hens per m2 in each winter garden (WG; WG 1: control, WG 2: double offer of the enrichment device, WG 3 and WG 4: single offer of the enrichment device) during the four phases. * = \(p<0.05\).  
Assuming an even distribution of animals over the whole WG area (160 m\({}^{2}\)), the approximate percentage of hens using the area simultaneously can be calculated. In phase A, on average, about 11.3% of the whole flock stayed in the WGs simultaneously, decreasing to on average 7.6% of all hens in the WGs in phase D. The highest number of hens was counted in phase C and WG 3, when a maximum of around 17.1% of hens used the area simultaneously.