## 4 Discussion  
The present study aimed to evaluate an automatic enrichment device dosing grain on PPs regarding its influence on the use of WGs by the hens. Moreover, the device's acceptance was studied by counting the number of hens, which used one PP simultaneously. These parameters were evaluated by comparing four WGs and four phases during the production period. For this purpose, the use of a certain area in which the enrichment device was provided and the number of animals close to the enrichment device were chosen as indicators. Based on the present results, an influence of the presence of the automatic enrichment device and the age of the animals on their number per m\({}^{2}\) could be verified. The amount of offered PPs (single vs. double) did not affect the use of the WGs. However,  
Figure 4: 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 pecking plate (PP). (**a**) During the 4 phases (A: the beginning of lay, B: peak of lay, C: middle of lay, D: end of lay) and (**b**) 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). \({}^{*}=p<0.05\). y = in WG 1, no PPs were installed, and no data was collected. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Phase**} & \multirow{2}{*}{**Mean (SD)**} & **Hens/PP in** & **Hens/PP in** & **Hens/PP in** & **Hens/PP in** \\  & & **WG 2** & **WG 3** & **WG 4** & **all WGs** \\ \hline A & / & 2.93 (1.94)a & 3.93 (2.36)a & 3.16 (2.18)a \\ B & 5.46 (3.72)a & 5.35 (2.93)b & 4.52 (3.27)b & 5.11 (3.37)b \\ C & 3.11 (2.9)b & 3.71 (2.42)c & 2.21 (2.41)c & 2.77 (2.62)c \\ D & 3.54 (3.08)b & / & 2.13 (1.72)c & 2.6 (2.36)c \\ \hline all & 4.6 (3.42) & 3.83 (2.59) & 2.82 (2.54) & / \\ \hline \hline \end{tabular} a.b.c Means in the same column with different superscripts differ significantly (\(p<0.05\)).  
\end{table} 
Table 3: Mean (Standard deviation) number of hens per pecking plate (PP) in the three winter gardens (WGs 2–4; 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). In WG 1, no PPs were installed, and no data was collected. more PPs could occupy more hens simultaneously. Other factors also influenced WG-use, such as the position of the WG. In the first two production phases (A and B), the number of hens per m\({}^{2}\) was significantly lower in WG 1 without PPs than in the other WGs with the enrichment device. Likewise, concerning PP use, the highest number of hens was also determined in phases A and B. Both results indicate a positive influence of the enrichment device on the use of the WGs by the hens. Thus, the enrichment device could allow hens to become more quickly accustomed to the WG area. Such an effect of enrichment was previously found with maize-silage offered various times a day, resulting in a higher occupation of the WG area [35]. The general interest in the WGs decreased during the end of lay, which matches findings about the use of the free-range decreasing with increasing age [41]. The interest in the pecking device decreased after the laying peak but stayed on the same level afterwards until slaughter despite decreasing numbers of hens per m\({}^{2}\), indicating a high attractiveness of the device. The difference in the number of animals per m\({}^{2}\) occurred not only between WG 1 (without an automatic enrichment device) and the other three WGs. This value also differed significantly between WG 4 and WGs 2 and 3 (all with PPs offered), especially during the peak and middle of lay. Therefore, other factors beyond the device's presence seem to have influenced the number of animals in the WGs, for example the WGs position within the henhouse. WGs 1 and 4 were positioned at the front of the henhouse, while WGs 2 and 3 were located at the back.