## 3 Results and Discussion  
### Biochemical Measurement  
Marked quality indicators show the freshness of both eggs from caged hens (eggs C) and free range hens (eggs F). Haugh units in the case of C and F egg whites were, respectively, 84.6 JH and 78.60 JH. The quality of protein in fresh eggs should be above 60 JH. Thus, all eggs tested, regardless of the housing conditions were characterized as having high quality egg whites. The measured pH of the C egg white was 8.11 and 8.19 for F eggs, and egg yolks (respectively 6.12, 6.07) confirm their quality for consumption and freshness. Selected qualitative features of egg yolks from caged hens (eggs C) and free range hens (eggs F) are presented in Table 1.  
An important factor determining the commercial quality of eggs is the yolk color, which is conditioned by the content of dyes (carotenoids). Consumers and industry prefer intensely stained egg yolks. The color is influenced by the method of feeding layers, the content of dyes in the feed, and access to free-range vegetation. In cage hens, feed supplements are used to color egg yolks in the form of synthetic dyes (canthaxanthin, apocarotenoic acid derivatives, e.g., beta-apo-8\({}^{\prime}\)-carotene acid ethyl ester and others) or natural ones. Red pepper fruits containing capsanthin or oleeresins extracted from edible raw materials rich in lutein (e.g., calendula) are used for laying hens. On the other hand, in free-range hen housing, hens can consume both feed enriched with colorants and, at the same time, depending on the season, enrich their diet with vegetation (including young false oat grass, white cress, red fescue, alfalfa, and dandelion) abundant in natural carotenoids [26; 27; 28]. It was determined that, in the case of eggs from caged hens, the yolk index was 8.00 points, and for from free-range hens, 9.00 points. [PERSON] and [PERSON] in their research show that the egg yolk index for eggs from free range hens is variable; it can be below 8 points and it is affected by poor vegetation on the catwalk, conditioned by seasonality [29]. The eggs analyzed were from September, so the laying hens from free-range housing probably had access mostly to green vegetation. In the present study, it was shown that the content of lutein was six times higher in egg yolks from free-range laying hens in comparison to eggs from caged hens, and the sum of carotenoids more than three times higher (Table 2). Lutein is naturally found in alfalfa, shrubs, and the green parts of plants, i.e., products to which free-range layers can have access, especially during the summer and early autumn. In addition, lutein is found in maize, which is usually a component of fodder, and can be found in various proportions along with synthetic dyes. \(\beta\)-carotene was not identified in egg yolks from free-range hens. The level of carotenoids in the diet has the greatest influence on the content of lutein in yolks. [PERSON] et al. demonstrated that higher content of carotenoids in the laying diet affects the color \begin{table}
\begin{tabular}{c c c} \hline \hline
**Features** & **Eggs C** & **Eggs F** \\ \hline  & egg yolk & \\ \hline Color of yolk & \(8.00\pm 0.30\) & \(9.00\pm 0.20\) \\ pH & \(6.12\pm 0.20\) & \(6.07\pm 0.08\) \\ \hline  & egg albumen & \\ \hline Haugh units & \(84.60\pm 0.59\) & \(78.60\pm 0.36\) \\ pH & \(8.11\pm 0.22\) & \(8.19\pm 0.38\) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Selected quality features of eggs, n = 60.  
intensity and lutein level in egg yolks [30; 31]. [PERSON] et al. showed that carrot supplementation increased the yolk content of lutein (>1.5-fold) and \(\beta\)-carotene (>100-fold) [32]. Other studies have shown that the content of carotenoids is higher in eggs of ecological husbandry compared to eggs of other systems (free range, barn, and caged). Similarly, total carotenoid concentrations of wild bird egg yolks were significantly higher compared to yolks from farm-reared birds, because wild birds have better access to various sources of natural carotenoids [33; 34].