A flying start : Adapted hatching and post-hatch feeding in broiler chickens

Conventional hatching practices do not involve provision of feed and water to broiler chickens before placement at the rearing farm. This can pose problems, especially for early hatchlings, which remain feed-restricted for a considerable period due to biological variation in hatch time. The individual requirements of modern fast-growing chickens in order to remain robust and resilient may have changed in recent decades. This thesis studied the effect of hatching time on interval to first feed intake, growth and organ development in chicks hatched on-farm. It also examined the effects of providing hatching chicks with access to feed and water in the hatcher, combined with two different probiotics, on productivity, organ development, immune traits and development of caecal microbiota. Physiological differences between chicks hatched at different times during the hatching window generally levelled out during the production period. Eating-related activities were low immediately post-hatch, and early hatchlings showed compensatory growth as they were lightest at hatch but heaviest at three days of age. Feed deprivation during hatch resulted in depressed feed intake and associated depressed growth, which in some cases was reversed during the growing phase. Supplementation with probiotics had some negative effects on productivity, especially for chicks deprived of feed and water at hatch. There were no long-term differences due to early feeding on microbiota development or immune traits measured. These results suggest that modern broiler chickens are at least partly capable of compensating for setbacks in early life, and that some early effects of feed and water deprivation are transient. However, the studies in this thesis were performed in highly sanitary conditions and at lower stocking densities than in commercial production. Further research is needed to confirm the effects of adapted hatching and post-hatch feeding strategies in conditions that resemble more closely the challenges faced by the modern broiler

Effect of a zinc amino acid complex on egg production, egg shell quality and external appearance in two laying hen genotypes housed in two different production systems

With an extended production cycle up to 100 weeks of age, the yearly number of layer chickens hatched and reared can be reduced, and in turn so can the euthanasia of day-old male chickens. Lately, the interest for keeping laying hens for a prolonged production cycle has increased in Sweden as well as in other European countries. However, concerns exist regarding how prolonged laying cycles affect egg quality, animal welfare as well as producer economy. In this trial, the two commercial hybrids LSL Classic and Bovans Robust were housed in furnished cages and a single tier floor production system. In addition to the effects of age, an organic mineral complex with a hypothesized positive effect on egg quality, integument and skeletal condition was evaluated. The study was conducted during 20-61 weeks of age. There were no consistent effects of the mineral amino acid complex supplementation on either egg quality, plumage condition or keel bone deformities at a hen age of 55 weeks. However, there were a lot of differences between hybrids regarding egg composition and layer performance in the two production systems. As expected and concluded in earlier research; egg shell quality, plumage condition and keel bone deformities were negatively affected by increased hen age

Effekt av gruppstorlek hos värphöns i inredda burar på välfärd och produktion

Den inredda buren är en kompromiss mellan frigående system och konventionella burar, och syftar till att ge hönsen möjlighet att i större utsträckning kunna utföra sina naturliga beteenden. Utanför Sverige är näbbtrimning vanligt förekommande och därmed även större gruppstorlekar. Det är av intresse att undersöka hur större gruppstorlekar skulle kunna tillämpas på den svenska modellen. Denna litteraturstudie har jämfört olika artiklar för att utröna om det förekommer en effekt av gruppstorlek på djurvälfärd och produktionsresultat. Djurvälfärd definieras i detta kandidatexamensarbete utifrån de fem friheterna. Forskningsresultaten har varierat och området är komplext. Stora grupper hönor hållna i inredda burar har i vissa försök visat sig fungera bra, medan det gett upphov till problem som till exempel fjäderplockning och kannibalism i andra försök. Många parametrar så som val av hybrid, burmodell, inredningsutformning och skötsel spelar in och interagerar, vilket gör det svårt att dra någon generell slutsats om enbart gruppstorlekseffekt. Mer forskning behövs kring vilka gruppstorlekar som är bäst lämpade för olika kombinationer av hybrid, inhysningssystem och burmodell.The furnished cage is a compromise between free-range systems and conventional cages, with the aim to facilitate the exercising of the hens’ natural behaviors. In other countries than Sweden, beak trimming is a common circumstance and, as a consequence, so is larger group sizes. It is relevant to investigate how larger groups of hens would impact the Swedish model. This thesis has compared different studies to examine the effects of group size on animal welfare and production output. In this thesis, animal welfare is defined based on the framework of the five freedoms. The results of existing studies differ, indicating a complex field of research with many variables. In some studies, larger groups of poultry have been proved to work well, while others show that increasing group sizes to a greater extent cause problems like cannibalism and feather pecking. Factors such as bird genotype, cage design and maintenance all interact and affect the results, making it hard to draw conclusions solely concerning the effect of group size. More research is required to determine appropriate group sizes for different combinations of genotypes, housing systems and cage models

Effects of algal supplementation in feed to broiler breeders on transfer of nutrients and antibodies to chicks and quality of hatchlings

Breeder nutrition is an important factor for chick quality since the chick embryo relies on nutrients available in the egg for growth and development. In addition, the egg is providing the chick with important antibodies that are vital during the first weeks of life. Brown algae contains several bioactive compounds, and dietary supplementation with algal extracts have shown improved gut health and immune responses in both pigs and poultry. The aim of this study was to investigate if feeding the brown algae Saccharina latissima, intact or as an extract, to broiler breeders can affect breeder hens' antibody responses to vaccination, egg quality and transfer of antibodies and nutrients to the egg and thereby improve the quality of newly hatched chicks. Forty-five hens and nine roosters of the parent lines of the fast-growing broiler Ross 308 were included in the experiment where hens were 31 weeks at the start. The hens were housed individually and fed one of three dietary treatments for seven weeks; (a) control, (b) addition of 0.6% algal meal or (c) addition of 0.08% algal extract. The hens were given a booster vaccination against infectious bronchitis virus (IBV) 21 days after the start of experiment. During experimental days 32-42, hens were naturally mated every 5th day and hatching eggs were collected. A total of 255 chicks were hatched, and chick quality was assessed. Moreover, on chick day three, blood was collected from 48 focal chickens and total immunoglobulin Y levels and specific titres to IBV in serum were determined. The results showed that feeding the brown algae Saccharina latissima, intact or as an extract to broiler breeders did not affect egg production, egg quality, antibody responses to vaccination or transfer of antibodies from hen to chick. However, feeding intact algae significantly increased the levels of iodine and decreased the level of selenium in the eggs and resulted in a lower proportion of chicks with maximum quality score. Interestingly, algal feeding, both intact and as an extract, increased the abdominal fat pad in broiler breeders by about 17% without affecting BW. In conclusion, supplementation of broiler breeder diets with algal extract from Saccharina latissima, but not intact algal meal is a promising dietary strategy to increase the abdominal fat pad without causing any adverse effects on nutrient level in eggs or chick quality. CO 2023 The Author(s). Published by Elsevier B.V. on behalf of The Animal Consortium. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

Effects of access to feed, water, and a competitive exclusion product in the hatcher on some immune traits and gut development in broiler chickens

1. This study evaluated the effect of access to feed, water, and the competitive exclusion (CE) product Broilact((R)), administered in the hatcher, on broiler performance, caecal microbiota development, organ development, intestinal morphology, serum levels of IgY and vaccine-induced antibody responses.2. In total, 250 chicks were hatched in a HatchCare (TM) hatcher and divided into four groups, given access to feed, water and the CE product sprayed on the chicks (CEs); access to feed, water, and the CE product in water (CEw); access to feed and water (Cpos); or no access to feed and water (Cneg) in the hatcher.3. At the research facility, 10 chicks per hatching treatment were euthanised for organ measurements. The remaining 200 chicks were randomly distributed to 20 pens. On d 11, all birds were vaccinated against avian pneumovirus (APV). Three focal birds per pen were blood-sampled weekly for quantification of IgY and serum antibodies to APV. On d 11 and 32, two birds per replicate pen were euthanised for organ measurements and sample collection. Feed intake and body weight were recorded weekly.4. Delayed access to feed and water reduced weight gain and feed intake early in life. At the end of the study, no differences in body weight remained.5. There were some early effects on organs, with depressed intestinal development and higher relative gizzard weight for the Cneg group at placement. No treatment effects on the immune traits measured were detected.6. The relative abundance of seven bacterial genera differed between treatment groups at d 11 of age. The results suggested that chickens are capable of compensating for 40 h feed and water deprival post-hatch. Provision of Broilact((R)) did not have any persistent performance-enhancing properties, although different outcomes under rearing conditions closer to commercial production cannot be ruled out

Integument, mortality, and skeletal strength in extended production cycles for laying hens - effects of genotype and dietary zinc source

1. This study on long-life layers, covering the period 20-100 weeks of age, investigated longitudinal effects on mortality, layer integument, and skeletal properties in Bovans White (BoW) and Lohmann Selected Leghorn Classic (LSL), with or without supplementation with dietary organic zinc (Zn). 2. Two experiments, using 1440 layers in furnished small group cages (FC) and 1836 layers in a traditional floor housing system (Floor), were run in parallel. Each replicate consisted of five adjacent cages containing eight hens in each FC, or a pen with 102 layers in the Floor group. 3. Mortality was recorded daily. Integument and keel bone condition were scored at 35, 55, 85, and 100 weeks of age on 20% of the layers. Tibial strength was recorded from 933 layers at 100 weeks. Statistical analyses were performed on replicate means, with four to five and nine replicates per combination of hybrid and diet in Floor and FC groups, respectively. 4. Cumulative mortality was 9.6% and 16.3% in FC and Floor, respectively, and increased in the latter part of the production cycle, particularly in the Floor group. 5. In FC, LSL had inferior feather cover, less keel bone deviation, and shorter claws than BoW. In Floor, LSL had superior feather cover, less severe vent wounds, more bumble foot, and cleaner plumage than BoW. In both production systems, claws grew longer and keel bone deviation became more severe with age. 6. In FC, layers fed organic Zn had lower body weight and less keel bone deviation at 100 weeks of age. 7. In conclusion, keel bone integrity, claw length, and mortality rate are potential threats to welfare in long-life layers. Feather pecking is a problem that needs addressing at an early stage in the production period. On the whole, organic Zn did not improve welfare conditions in long-life layers

Effect of hatching time on time to first feed intake, organ development, enzymatic activity and growth in broiler chicks hatched on-farm

The conventional commercial hatcheries used today do not allow the newly hatched chicks to consume feed or water. Combined with natural variation in hatching time, this can lead to early hatched chicks being feed-deprived for up to 72 h before being unloaded at the rearing site. This study investigated the effects of hatching time on time to first feed intake and development of organs, digestive enzymes and productivity in terms of growth and feed conversion ratio in chicks hatched on-farm. Chicks were divided into three hatching groups (early, mid-term and late), and assessed over a full production cyde of 34 days. The results revealed that chicks remain inactive for a considerable amount of time before engaging in eating-related activities. Eating activity of 5% ( i.e. when 5% of birds in each hatching group were eating or standing dose to the feeder) was recorded at an average biological age (BA) of 25.4 h and a proportion of 50% birds with full crop was reached at an average BA of 30.6 h. Considering that the hatching window was 35 h in this study, the average chick probably did not benefit from access to feed and water immediately post-hatch in this case. At hatch, mid-term hatchlings had a heavier small intestine (30.1 g/kg bw) than both early (26.4 g/kg bw) and late (26.0 g/kg bw) hatchlings. Relative length of the small intestine was shorter in late hatchlings (735 cm/kg bw) than in mid-term (849 cm/kg bw) and early (831 cm/kg bw) hatchlings. However, the relative weight of the bursa fabridi was greater in mid-term (130 g/kg bw) than in early hatchlings (1.01 g/kg bw). At hatch, late hatchlings were heavier than early and mid-term hatchlings (P < 0.05), but by 3 days of age early hatchlings were heavier than mid-term and late hatchlings (P < 0.01). The only effect persisting throughout the study was a difference in the relative weight of the small intestine, where late hatchlings had heavier intestines than early hatchlings (P < 0.05). Thus, while there were differences between hatching groups, this study showed that the hatchlings seemed capable of compensating for these as they grew. (C) 2020 The Authors. Published by Elsevier Inc. on behalf of The Animal Consortium