Heat stress can greatly challenge growth and meat quality of broiler chickens where research is looking for sustainable ingredients, such as microalgae, that could also alleviate its negative impacts. Thus, in the present study, 576 1-D-old chicks (Ross 308) were housed until commercial slaughtering (42 D) in 36 pens in 2 rooms of a poultry house, according to a full factorial design encompassing 2 room temperatures (standard vs. high), 2 sexes (females vs. males), and 3 dietary treatments, that is, diet C0 (control diet), diet C3, and diet C6 containing 0, 3, and 6%, respectively, of C. vulgaris meal replacing the same quantities of soybean meal. The highest inclusion level of C. vulgaris decreased feed intake (P < 0.001) and body weight (P < 0.0001) compared to the control diet; it increased yellow and red indexes (P < 0.0001) of the breast muscle, besides the proportion of n3 polyunsaturated fatty acids (PUFA) (P = 0.028). Heat stress decreased feed intake (P = 0.001), breast (P = 0.001) and p. major yields (P = 0.036), and increased meat pH (P= 0.008) and cooking losses (P < 0.001), umami (P = 0.021) and brothy flavor (P < 0.001), and the proportion of n3 PUFA rates (P = 0.027), while reducing the contents of several amino acids in the breast meat (P ≤ 0.05). Compared to females, males displayed higher feed intake and growth, and more favorable feed conversion (P < 0.001). Carcass and p. major yields were greater in females (P < 0.001) which also showed a higher occurrence of spaghetti meat compared to males (P < 0.001). In conclusion, C. vulgaris can be used to replace until 3% of soybean meal in diets for broiler chickens without negative implications, while positively affecting breast meat color according to consumers' preferences. However, the microalgae inclusion did not mitigate the negative effects of a chronic heat stress on growth performance nor reduced the occurrence of any myopathies.

This study assessed environmental gradients at different heights in a multi-tiered aviary and their relationship with hen spatial distribution. Two pens of an experimental aviary housing 225 Novogen hens (Novogen S.A.S., Plédran, France) each were monitored when their hens were 32–52 weeks old over three periods (January, March, and June). The environmental conditions (humidity, sound intensity, NH₃, CO₂, and particulate matter; PM: PM₁, PM_2.5, PM₄, and PM₁₀) were continuously recorded every 10 min, 24 h per day, at three heights (floor and middle and upper tiers) using an IoT-based system. Hen distribution was analysed using video recordings from 04:00 to 20:00, scanning 15 min for every 30 min of video. On the whole, the air quality was always consistent with the recommended values for laying hens. The middle tier, where nests were located, exhibited a higher humidity and CO₂ and PM concentration compared to the upper tier and floor, suggesting reduced airflow. This result can be related to the reduced length of the experimental barn containing only one row of equipment, which likely affected air circulation and distribution compared to what happens in commercial barns with several rows and a length over 50 m. Hen distribution varied during the day, with hen presence on the floor being highest in the midday (58% of hens) and correlated with increased particulate matter (r = 0.57–0.60; p < 0.001) and NH₃ concentrations (r = 0.33; p < 0.001). Hens occupied the upper tier more in June (34% vs. 24% in January; p < 0.001), correlating with lower humidity and PM levels. Understanding daily and seasonal changes in environmental gradients at different aviary tiers could help optimise ventilation schemes and air quality control and ensure hen welfare, health, and production throughout the laying cycle.

To evaluate the effect on egg quality of the dietary supplementation with whole hempseeds, as an environmental and nutritional enrichment, a 4-week trial was implemented in an aviary housing a total of 1800 Hy-Line Brown hens in 8 pens (225 hens/pen). From 37 to 40 weeks of age, four pens received only a commercial diet (Control group) and the remaining four pens received whole hemp seed (HS group) (10 % of the average daily feed intake of the whole group) once per day in two additional circular feeders (two pens) or directly on the ground (two pens). Then, for the specific purposes of the presents study, after 14 and 28 days of trial (60 eggs/pen per sampling), a total of 480 eggs were collected from two pens of the control group and the two pens of the HS group fed hemp seeds in the circular feeders. On average of the two samplings, the hempseed enrichment did not influence most egg quality traits, i.e. proximate and mineral composition of egg yolk (P > 0.05), while it reduced the L* index and the pH of yolk (P < 0.001) and increased the pH of albumen (P < 0.05). Additionally, in yolk, hempseed enrichment decreased the proportion of total saturated (P < 0.001) and monounsaturated fatty acids (P ≤ 0.05), whereas it increased the proportion of n-3 (P < 0.001) and n-6 polyunsaturated fatty acids (P ≤ 0.05) compared to hens of the control group. Sensory evaluation of boiled eggs showed that 46 % of the participants noted the difference between eggs from hens receiving or not the hempseed supplementation (P ≤ 0.05), but one sample was not preferred over another (P > 0.05). In conclusion, the enrichment after four weeks with whole hempseeds at 10 % of the daily feed intake in laying hens improved the fatty acid composition of yolk lipids without affecting the majority of egg quality traits and consumers' preferences.

Keel bone lesions (KBLs) represent a relevant welfare concern in laying hens, arising from complex interactions among genetics, housing systems, and management practices. This study presents the development of an image analysis system for the automated detection and classification of KBLs in slaughterhouse videos, enabling scalable and retrospective welfare assessment. In addition to lesion classification, the system can track and count individual carcasses, providing estimates of the total number of specimens with and without significant lesions. Videos of brown laying hens from a commercial slaughterhouse in northeastern Italy were recorded on the processing line using a smartphone. Six hundred frames were extracted and annotated by three independent observers using a three-scale scoring system. A dataset was constructed by combining the original frames with crops centered on the keel area. To address class imbalance, samples of class 1 (damaged keel bones) were augmented by a factor of nine, compared to a factor of three for class 0 (no or mild lesion). A YOLO-based model was trained for both detection and classification tasks. The model achieved an F1 score of 0.85 and a mAP@0.5 of 0.892. A BoT-SORT tracker was evaluated against human annotations on a 5 min video, achieving an F1 score of 0.882 for the classification task. Potential improvements include increasing the number and variability of annotated images, refining annotation protocols, and enhancing model performance under varying slaughterhouse lighting and positioning conditions. The model could be applied in routine slaughter inspections to support welfare assessment in large populations of animals.

The effect of the enrichment (10% ad libitum daily feed intake) with live larvae of Hermetia illucens (HI) was evaluated on behavior, egg production and quality from 36 to 40 weeks of age in 1800 laying hens of two genotypes (brown and white) randomly allocated in 8 pens of an aviary system. The larvae enrichment significantly affected space use and behavior, increasing the number of birds on the floor (P < 0.001), the proportion of clean eggs and that of eggs laid in the nest (P = 0.001), while reducing inactivity, floor pecking and the distance hen-operator at the avoidance test in enriched compared to non-enriched pens. As for differences between genotypes, the rate of inactive hens was higher (P = 0.001) in brown compared to white hens, while the rate of hens pecking the floor and showing preening was lower (P < 0.001). The number of piling events was markedly lower in brown compared to white hens (P < 0.001) and brown hens were also more likely to approach a novel object (P = 0.044). Then, brown hens showed higher rates of broken eggs (P = 0.008), fewer eggs laid in nests and more eggs laid on aviary tiers (P < 0.001). Egg quality differences were limited with more blood and meat spots (P < 0.001), lower yolk proportion (P < 0.001) and thicker shells (P < 0.001) in brown compared to white hens. In conclusion, the enrichment with HI live larvae increased species-specific behaviors in both genotypes without substantially affecting egg production and/or quality. On the other hand, the enrichment improved the space use as eggs laid in the nests increased at the expenses of floor eggs, which finally resulted in an improvement of production.