Iwona Skomorucha

The growing greenhouse gas emissions from agricultural production are increasing the pressure on poultry producers to use practices that reduce the environmental impact of farms, mainly by reducing ammonia emissions. The study evaluated the effect of adding effective microorganisms (EMs) and zeolite to litter on productivity, meat quality, selected physiological parameters, and air and litter quality in broiler chickens. In the experimental group, zeolite was applied at 3 kg/10 kg to the litter, and it was sprayed with a solution of EMs and water in a 1:4 ratio. Spraying was repeated weekly until the end of the production cycle. The litter additives reduced the moisture content and pH of the litter (p < 0.05) in the experimental group. This group also showed lower air humidity (p < 0.01) and reduced levels of ammonia and carbon dioxide compared to the control group (p < 0.05). A positive effect of litter additives on production results and the health of broiler chickens was noted. In summary, the addition of 3 kg/10 kg of zeolite to the litter, combined with spraying the litter with a 1:4 solution of EMs and water, can contribute to reducing the emission of harmful gas admixtures generated on broiler farms without negatively affecting production efficiency.

The aim of this study was to evaluate the effect of the origin of hens of locally adapted breeds on the levels of selected stress indicators and neurotransmitter serotonin in blood, and also on the selected behaviour and plumage condition. A total of 168 one-day-old chicks of the hens Leghorn H-22, Sussex S-66 and Rhode Island Red R-11 were allocated to three experimental groups, respectively: 1, 2 and 3. The birds were reared on litter until 64 weeks of age. Bird mortality was monitored during the experiment, the duration of tonic immobility (TI) was measured and blood was collected and the following were determined: heterophil-to-lymphocyte ratio (H:L), levels of corticosterone, adrenaline, noradrenaline and serotonin. Behavioural observations were also made and the plumage condition of the hens was also assessed. The hen strains studied showed different levels of fear and stress during rearing, as reflected in the behavioural test carried out and the blood levels of basal corticosterone, noradrenaline and the H:L ratio. It was also shown that changes in the birds’ fear and stress response strategies can occur with age. H-22 hens showed greater fear and stress at both young age and adulthood, and were characterised by poorer plumage and higher mortality during rearing. The results, therefore, suggest that strain H-22 has a greater propensity to develop stereotypes such as feather pecking compared to strains S-66 and R-11.

The aim of the present study was to determine the effect of rearing technology (rearing system and dietary supplementation with a mixed herbal extract) on the production results, selected physiological and blood parameters, and welfare of broiler chickens during the summer production cycle. In the CON and HE groups, broiler chickens were kept on litter without access to free range; additionally, in the HE group, birds from 22 to 42 days of rearing received a mixed herbal extract (50% Melissa officinalis L. and 50% Urtica dioica L.) in the amount of 2 ml/l of water to drinkers with water. In the AP group, birds were reared on litter with access to pasture. During the experiment, production performance and body temperature of the birds were monitored. Blood was also taken from birds in each group and the H:L ratio, levels of corticosterone, glucose and thyroid hormones were determined. The application of 2 ml/l of mixed herbal extract to the drinking water did not improve the production results, nor did it affect the physiological indices of the birds studied. The addition of 2 ml/l of mixed herbal extract to the drinking water only resulted in lower corticosterone levels in the blood of the chickens on day 35 of the experiment. The free-range housing system had a negative effect on the slaughter performance of the broiler chickens. However, housing with access to the free range resulted in lower body temperature, lower mortality, as well as lower glucose, corticosterone and a narrower H:L ratio in the blood of the chickens during the period of increasing air temperature. It can therefore be concluded that housing with access to a free range reduces stress levels and thus improves the welfare of broiler chickens during the summer production cycle compared to confined housing. Comparing the rearing technologies used in the study, it was found that the free-range housing system contributed more to improving the comfort of broiler chickens during the summer than dietary supplementation with the tested herbal mixture extract.

The aim of this study was to evaluate whether production costs can be reduced and whether the profitability of organic chicken fattening can be increased by selecting the appropriate genotypes. Rhode Island Red (K-11) and Sussex (S-66) conservative chicken genotypes, as well as modern chicken genotypes such as slow-growing Hubbard JA 957 hybrids and fast-growing Ross 308 hybrids, were selected for the study. One hundred and sixty chickens were used in the experiment (forty birds per group). The birds were fed commercial organic complete feed up to 52 days of age and organic farm-made feed (to reduce costs) between 53 and 81 days of age. Population distribution was determined using the Kolmogorov–Smirnov test. The results were analyzed statistically using one-way analysis of variance (ANOVA) with multiple comparisons and the post hoc Tukey test at a significance level of p < 0.05. The 81-day fattening period (the minimum recommended period in organic farming) led to considerable weight deficits in Rhode Island Red and S-66 chickens and excessive slaughter/trade weights in Hubbard JA 957 and Ross 308 chickens. The feed conversion ratio was high in Rhode Island Red (K-11) and Sussex (S-66) chickens at 4.19 and 4.50, respectively, and much lower in Hubbard JA 957 and Ross 308 chickens at 2.79 and 2.53, respectively. The choice of chicken genotypes had a major impact on the profitability of organic farming, and the total costs of feed and other ingredients per kg of body weight were determined at EUR 3.83 for Rhode Island Red (K-11), EUR 3.90 for Sussex (S-66), EUR 6.57 for Hubbard JA 957, and EUR 6.62 for Ross 308 genotypes. The profitability of organic farming can be increased by selecting modern, meat-type, slow-growing chicken genotypes.

The aim of the conducted research was to assess the impact of the botanical composition of free-range areas on the production results and selected quality parameters of the meat of fattening chickens of the Polish Yellowleg Partridge (Ż-33) breed in organic farming. Three hundred mixed-sex Ż-33 chicks were assigned to three groups: RP1 – free-range area with natural meadow vegetation, RP2 – free-range area sown with a mixture of plants containing ingredients stimulating growth, RP3 – free-range area sown with a mixture of plants rich in carotene. During the experiment, the production results (the weight of the birds, feed consumption, feed conversion ratio per g of weight gain, and mortality) were monitored. Observations were also performed on the behaviour in the free-range areas. On the 140th day of the experiment, a simplified slaughter analysis was carried out, the meat pH was measured, the colour of the muscles was also determined, as well as the water holding capacity and drip loss of the meat. In the meat samples, the content of nutrients and fatty acids was determined, and the peroxidizability index (PI) was calculated. Birds feeding in the RP2 free-range areas were characterised by higher body weight, better feed conversion, and higher dressing percentage compared to birds having access to the RP1 and RP3 free-range areas. On the other hand, the RP3 group Ż-33 chickens were characterised by a higher share of leg muscles and a tendency towards lower fat content in the carcass. It was also found that the meat of birds from the RP2 and RP3 groups was characterised by a higher pH ₂₄ compared to Ż-33 chickens from the RP1 group. Access to the RP2 free-range area modified the fatty acid profile, mainly in the leg muscles, reducing the palmitic acid and MUFA content and increasing the PUFA content. It can therefore be assumed that the plant species sown in the RP2 free-range area positively influenced the production results and the quality of the meat of fattening chickens feeding on them. It is therefore appropriate to carry out further studies on the type of vegetation sown in free-range areas in order to improve the efficiency and quality of the meat of organic fattening chickens.

Sudden death syndrome (SDS) is a condition in which apparently healthy broiler chickens die suddenly. There are short convulsions and frantic wing-beating prior to death, and the weight of internal organs is the same as in healthy chickens. The exact etiology of SDS is unknown. Heart problems have been implicated as a potential cause of the disease in broiler chickens. Despite considerable research, effective methods of prevention are still being sought. Furthermore, the prophylactic measures often make production less profitable (reduced body weight gain resulting from restricted feeding) and prolong the growth period. It is necessary to continue research on SDS, in particular on stimulation of the cardiovascular system to reduce the susceptibility of broilers to sudden death syndrome under intensive production systems.

The effects of the in ovo injection site of electrolytes on selected biochemical blood parameters and the quality of layer chicks were investigated. A total of 120 fertile eggs from Rhode Island Red breeders were randomly distributed into 4 groups, with each group including 30 birds. The groups were as follows: untreated control and groups with different injection sites/locations of 500 µL of 0.9% saline (NaCl) on day 18 of incubation, i.e., into the air cell (AC), through the air cell into the amniotic fluid (AFA), and directly into the amniotic fluid (AF). Measurement at 1 day of age showed that regardless of the injection site, embryos injected with 500 µL of saline had significantly higher Tona score (95/100 points) compared to the control group (90/100 points). Chick length was similar among the injected groups (mean 14.7 cm) and shorter in the control group (13.9 cm). There was no significant effect of in ovo injection on the biochemical blood parameters: total protein, cholesterol, high-density lipoprotein, low-density lipoprotein, glucose, urea, and uric acid. The highest concentration of sodium was noted in the control group (141.59 mmol/L). Regardless of the injection site/location, chicks treated with 500 µL of NaCl were characterized by a significantly lower blood sodium concentration (by 7.45% (AC), 7.90% (AFA), and 4.84% (AF) compared with birds from the control group (p ≤ 0.01)). The influence of saline solution administration in ovo on the blood potassium content of chicks was demonstrated. The concentration of potassium in the control group was significantly higher (by 11.36%) than in the AC group (p ≤ 0.01). In conclusion, the injection of 500 µL of saline solution into the developing chick embryo during the last days of incubation may have a positive effect on the quality of day-old chicks.

The currently used poultry farming methods, which aim to maximise economic profit, are based on ever new technological solutions that improve flock management and increase bird performance. However, they do not always meet the natural needs of birds. Every housing method and technological solution currently in use is faced with some issues, such as social stress, adverse temperature/ humidity conditions, risk of zoonoses, and behavioural pathologies, which determine poultry performance and welfare. Disregard for animal welfare involves not only ethical but also practical aspects, because well-being and housing comfort translate into better weight gains, health and productivity of the birds. The studies reported here suggest that every production system, despite the many welfare-improving aspects, causes numerous behavioural, productivity and health abnormalities in laying hens. Therefore, further research is needed to identify various risk factors for the purpose of improving housing systems and increasing the welfare of hens.