In order to achieve the proposed objectives, experiment duration of 22 weeks was conducted at the Central Poultry Development Organization and Training Institute (CPDO & TI) Hessaraghatta Bengaluru. The experimental procedures and analytical techniques adopted during the course of the study are detailed here. The trial was conducted by using Hessaraghatta hybrid−260 (HH260, White Leg horn breed) layer breeder birds. Eighteen week layer breed numbering 290 (250 females+40 males) were housed in shed No-2 having dimension of 20 ft × 50 ft. The birds with an average body weight of 1.1 to 1.3kg were selected randomly and assigned to 2 groups (T1- Conventional rearing system and T2-Automated rearing system), one each for automated and conventional system, with 5 replicates in each group and having 25 female and 4 males in each replicate (125 female per treatment). The chicks were reared in open sided house under deep litter system with all standard management practices till 40 weeks of age. Standard vaccination schedule was followed for immunizing the chicks. Birds were fed with layer breeder ration diet from eighteen weeks @ 120 gm/ bird/day. Feeding of diets commenced at eighteen week of age and continued till the termination of experiment at forty weeks of age.

Body weight: The effects of different rearing system (Table 2) on the mean body weight from eighteen to forty weeks of age on weekly basis were significantly (P≤0.05) influenced among the various treatment groups in HH260 birds. The body weights of both the treatment groups were uniform till thirty weeks (P≤0.05). From thirty-one to forty weeks optimum body weight achieved in birds reared in automatic rearing system as compare to birds reared in conventional rearing system. This shows that the uniform feeding achieved in automatic rearing system as compare to conventional rearing system.

The results of present study are in agreement with Lacin et al. (2008) findings as uniform feeding has positive influence on achieving optimum body weight. Leeson and Summers (1991) and Harms et al. (1984) noted that there was a significant relationship between feed consumption and body weight. Maximum body weight was found in T₁ group (ARS) which was not significantly high as compared to T₂ group groups during forty week of the experiment. Anderson and Adams (1994) indicated that birds provided with more feeder space will gain the bodyweight faster in white leg horn birds. This follows the same trends found by Anderson and Adams (1992) i.e., (Body weight differences manifested at the end of the rearing period remained through the production cycle). They also concluded that ending BW and BW gain were not affected by the type of flooring material. In contrast of Meunier-Salaun et al. (1984), who reported that the rearing environment had no significant effects on hen performance. Breeder management guide programs have suggested that optimum feeder space will ensure that all chicken have access to the feed and that feeder space should increase as the chicken’s age (Anonymous, 1997). Furthermore, inadequate feeder space has been generally associated with poor uniformity of flock BW (Anonymous, 2009), but a controlled study found that significantly reduced feeder space had no effect on BW uniformity (Van Krey and Weaver, 1988). Singh et al. (2009) also reported that the body weight of hens will be affected by different rearing system. Uniformity of body weight in pullets and layers is of an important managerial concern (Sosnówka et al., 2010). However, on contrary (Adam, 2017) study showed no significant differences in body weight gain during the experimental period for layers housed in different rearing system.

Feed Conversion ratio: Statistical analysis revealed significant difference (P≤0.01) in mean FCR values (Table 3) among the two treatment groups during twenty third week, twenty nine week, thirty week, thirty one week, thirty nine and forty week. The patented Roxell Haikoo feeder® designed in such a way that it accommodate more number of birds compare to conventional feeders, which further leads to the optimum feed utilization by the birds. The results of present study are in agreement of Sonkamble et al. (2020) findings that feed conversion ratio in terms of feed intake/ egg was influenced by type of rearing systems. Contrary to our findings in this experiment, the results of the present study are in disagreement with Ahammed et al. (2014) who reported that there was no significant difference in feed conversion ratio in birds reared in different rearing systems. Conflicting reports from those authors is likely due to the influence of a variety of factors, such as genetics, nutrition, environment, and age (Rakonjac et al., 2017). Regarding the genetics of the bird, it is suggested that commercial strain, selected for production under intensive controlled conditions, seem to be inappropriate for alternative and enriched rearing systems, which provide more natural but poorer living conditions (Hovi et al., 2003). However, there was no information regarding the effect of automatic rearing systems on white leghorn chicken (HH-260). Although many researchers have studied laying hen performance response to automatic and alternative rearing systems such as enriched cage, aviary, floor management, and free range systems (Tauson et al., 1999; Neijat et al., 2011; Ahammed et al., 2014), studies on the effect of changing from conventional cages to automatic rearing systems on production traits are continuing, especially in relation to the ability of pure inbred breeds to adapt to these automatic systems under certain climates. Hens under automatic rearing systems (ARS) showed higher FCR, this was probably due to the higher motor activity (Castellini et al., 2006) of the hens of this group. This statement is consistent with report from Lampkin (1997) and Mugnai et al. (2009).

This study shows the ability of layers hens to regulate the intake of nutrients which can be used to increase feed efficiency. Greater levels of comfort behaviours such as resting, and preening, perching and mud bathing had shown improved FCR in the white leg horn birds. Clark et al. (2019) also had similar study and concluded that significant impact of comfort behaviours such as resting, perching, mud bathing and preening on Feed conversion ratio. Poultry birds are good foragers and converters of feed into bio-available protein in meat and egg (Abanikannda et al., 2007). Feed conversion ratio for the entire laying period, the best-feed conversion ratio was observed in layers reared in deep-litter system (Adam, 2017). Also report noted by (Gerzilov, 2012) the feed conversion ratio in layers kept in deep-litter was high versus other both poultry housing systems.

Age at sexual maturity: Age at first egg of the experimental birds (Table 4) was considered as age at sexual maturity during the study. There was no significant difference observed in age at sexual maturity in relation to the rearing system. Age at first egg in both the treatment group did not have impacted on experimental birds since all the experimental birds selected at the age of eighteen weeks. And also, automatic and conventional rearing system did not have significant effects on age at fifty per cent production. The result of the study is in agreement with the findings of Sonkamble et al. (2020) as the rearing of birds in different housing system did not have significant effects on age at first egg and age at sexual maturity. Similar results were reported by Anderson and Adam (1994) that rearing feeder space had no effect on the age at 50 per cent production and age at sexual maturity. On contrary to these findings, DeAvila et al. (2003) reported that feeding time and frequency triggers early sexual maturity in female broilers breeders.

Egg Production: Egg production in experimental birds (Table 5a) in automatic rearing system was significantly different (P≤0.05) from birds reared in conventional rearing system. Similarly, Hen housed egg production and Hen day egg production (Table 5b) was significantly higher (P≤0.01) in automatic rearing system as compare to conventional rearing system. The result of the study are in agreement with the findings of Idowu et al. (2018) as rearing system have positive correlation to the egg production. Similar study conducted by Englmaierová et al. (2014) reported the highest hen day egg production found in enriched rearing system than other rearing system. Egg production is partly productive and partly reproductive trait (Bell et al., 2007). Improving feed conversion ratio and achieving optimum body weight will improve the total egg production. It can be statistically induced that selection for improving one trait will simultaneously improve the other traits and otherwise. This result agrees with Jahan et al. (2017). However, on contrary to the findings of Du Plessis, (1972) reported that there is no relationship between total egg production and body weight at sexual maturity. Some studies (Abrahamsson et al., 1996; Tauson et al., 1999) have reported that egg production of laying hens was influenced by rearing system. The managemental factors like optimum feeding, watering and less manhandling will reduce the stress in the birds which in turn reduce the plasma cortisone level of the experimental birds (Scanes, 2016). Tactacan et.al. (2009) studied the comparison of conventional versus enriched house concluded that there was no marked difference in hen day egg production. Poultry hen requires about 24 to 26 hours for producing an egg. After the egg is laid, the hen starts all over again about 30 minutes later (Bell et al., 2007).Egg production is a dependent variable and is influenced by several factors like strain of chicken (Shah et al., 2006; Petek, 1999), feeding, mortality, culling, health and management practices, age at point-of-lay, and peak for lay and persistency of lay rate (Kristensen and Silleb-Kristensen 1996). Some important factors from the managerial point of view efficient operations, resources utilization, economical feeding, improved housing and standard stocking density rate (Eekeren, 2006). Egg production can be environmentally affected by factors such as quality and quantity of poultry feed, water consumption intensity, photoperiodism and diseases (Kekeocha, 1984). In contrast to the findings of Sonkamble et al. (2020), who reported that the average hen day and hen house egg production were not affected due to different housing systems. Similar study reported that egg production of hens showed no difference under different rearing systems (Neijat et al., 2011; Ahammed et al., 2014).

Litter Quality: Litter quality analyzed based on the proximate analysis and Ecoli count and found significant difference (Table 6a & 6b) among the two-rearing system (P≤0.01).The proximate analysis of built up litter was significantly higher (P≤0.01) in conventional rearing system than the automatic rearing system. The higher proximate values like crude protein, crude fat, crude fibre, total ash and energy value were mainly due to feed wastage in conventional rearing system which leads to elevation of these values. The results of the study of Ensimnger (1977); Devendra and Raghavan (1978); Lamidi (1995) all reported approximately 25 per cent crude protein for poultry litter. The differences in the proximate content of poultry litter used in this study (20 per cent) when compared to the findings of other authors as cited above could be attributed to the difference in the type of bedding material, feed wastage, the type of rations used, method of handling and method of processing and storage of the poultry litter. However, the feed wastage is the major attributed factor for the high value of proximate principles in the poultry litter in conventional rearing system. (Cole et al., 2009) claimed less feed wastage due to special patented designed which doesn’t allow feed to drop outside the feeders. Saleh et al. (2002) who compared the nutritive contents of poultry litter obtained Crude Protein scores of 23 per cent. The total ash content provides important data and information about the quality of poultry litter. This is because it measures the mineral content of the litter. Ash is normally high in poultry litter because of the paddy husk. In this study, the ash content of the litter was 18.40 per cent in automatic rearing system to 19.09 per cent in conventional rearing system. Ash samples between 15-25 percent are acceptable (Ruffin and McCaskey, 1990). This finding is in line with their recommendation and they further observed that high ash content (above 28 percent) too dry litter causes respiratory and eye irritation to the poultry flock. With respect to the Dry Matter content, the study observed a DM content of 79.70 to 81.8 per cent in automatic and conventional rearing system, respectively. This means that the poultry litter had 18.20 and 20.30 per cent moisture in automatic and conventional rearing system respectively. From earlier reports Ruffin and McCaskey (1990); Burdine et al. (1993); Bagley et al. (1994), it was concluded that moisture in the litter should be between 12 and 25 percent. Results obtained in the present study are strongly in agreement with their findings. The E.coli count in conventional system was significantly higher than in automatic rearing system (P<0.05). Bell et al. (2007) reported that drinking water, human handling and in ovo route are the important mode of transmission of E coli. The usage of nipple drinkers in automatic rearing system reduces the microbial contamination. Controlling bacterial load is much more difficult with open drinker systems as they are exposed to contamination by faecal dust and the oral and nasal secretions of birds as they drink. Closed nipple systems have the advantage of reducing disease spread since these systems will always equipped with filtration system (Goan, 1994). This statement can be conclusive with the work of Macari and Amaral, (1997) who compared the nipple drinkers versus bell drinker in commercial poultry farms and concluded that E.coli count in bell drinkers 10⁵ times more than nipple drinker system. The oocyst of coccidia was not found during entire study period and concluded that there is no significant evidence to support the viability of oocyst in automatic and conventional rearing system. Alternatively, moisture is less than 20 per cent attributed to the non viability of the coccidial oocyst. Result of the study is in consonance with Reyna et al. (1983) who reported that viability of coccidial oocyst are 100 per cent declined in litter having moisture less than 20 per cent. The working time measurement for feeding was observed to be 8.4 man power minutes per day for T₁ group of automatic rearing system as compare to 22 minutes man power minutes per day in T₂ group of conventional rearing system. Machine known for precision and accuracy in less time, however no studies reported so far. Statistical analysis reveals that the values are highly significant (P≤ 0.01) among the treatments.

Liveability: The liveability rate (Table 7) of the experimental birds was significantly higher (P≤0.05) in automatic rearing system than the experimental birds in conventional rearing system. The high liveability rate in automatic rearing system is mainly due to less manhandling and human contamination. Nipple watering systems are more hygienic water delivery system for commercial poultry. (Cobb breeder management guide, 2009). This is in contrast with reports of (Tanaka and Hurnik, 1992; Abrahamsson et al., 1995), which found that mortality, can be low in alternative housing systems such as Aviary and enriched housing system.

However, mortality is caused by several components and it is difficult to categorize the real causes according to housing systems. Another study from Tauson et al. (1999) found that the overall higher mortality of Lohmann Brown hens in floor pens than in cages is largely due to cannibalism and feather pecking with no difference between housing systems. To ensure health and optimum egg quality the water supplied to the hens should be of potable standard (Thiele and Pottguter, 2008). The overall symmetry and mechanisms of immune system in birds are relatively similar to those in mammals which is directly influenced by genetic, physiological, nutritional, and environmental factors (Qureshi et al., 1998; Rautenschlein et al., 2003). The immune system of birds is complex and is composed of several cells and soluble factors that must work together to produce a protective immune response. A well developed and functional immune system is important to poultry because most commercial flocks are raised under intensive rearing conditions. Under such conditions, the flocks are vulnerable to rapid spread of infectious agents and disease outbreaks (Rautenschlein et al., 2003). Contrary to these findings, Platz et al. (2009) reported that the assessment of healthiness of hens housed in furnished houses did not indicate any significant advantage over those housed in aviaries. The working time measurement for feeding was observed to be 8.4 man power minutes per day for T₁ group of automatic rearing system as compare to 22 minutes man power minutes per day in T₂ group of conventional rearing system. Machine known for precision and accuracy in less time, however no studies reported so far. Statistical analysis reveals that the values are highly significant (P≤ 0.01) among the treatments.

The result of the present study indicated that automation rearing system for commercial poultry is beneficial for eliciting optimum production performance in HH260(white leg horn) Breeder birds. It accepted the hypothesis of the study that ARS housing have better productivity and profitability over conventional, this is testified by the general better FCR, egg production, liveability and litter quality in CCS houses.