The aim of the present study was to evaluate the performance of three chicken genotypes under free range, semi intensive and intensive housing systems. The study was included three experiments; in Experiment I, the effects of housing systems (free-range, semi-intensive and intensive) on performance of early-phase chickens (7-16 weeks of age) over 10 weeks were compared across sex (cockerel vs. pullet) and genotype [purebred Naked Neck (NN) and two crossbreds Rhode Island Red × Naked Neck (RIR × NN = RNN) and Black Australorp × Naked Neck (BAL × NN = BNN)]. Twenty birds were assigned to each of the 18 treatments (housing system [3] × sex [2] × genotype [3]; n = 360 total birds) in a Randomized Complete Block Design (RCBD). Body weight, behavioral repertoires (walking, jumping, running, drinking, feeding, standing, sitting, aggressiveness, dust bathing and wing flapping), morphometrics (body, shank, keel, neck, drumstick and beak length, shank, and drumstick circumference, wing spread and body weight) were measured weekly. At age of 16 weeks, 3 birds from each treatment (n = 54); were euthanized and carcass characteristics [weight at slaughter, dressed weight, carcass yield, giblets weight (liver, gizzard and heart), breast, drumstick, thigh and wings] were also evaluated. In Experiment II, the influence of housing systems on performance of different genotypes (NN, RNN & BNN) were observed from 17-21 weeks, similarly as described earlier in experiment I (n =260 birds). Blood samples were collected from 27 pullets to evaluate serum chemistry (glucose, total protein, albumin, globulin, uric acid, creatinine and cholesterol) and antibody titers against Newcastle Disease and Infectious Bronchitis. Experiment III, was the continuation of experiment-II, where 260 birds were used. Out of these 260 birds, 180 birds (48 pullets and 12 cockerels from each of 3 genotypes) were moved to breeding coops at ratios of 4 pullets to one cockerel. The effects of housing system on different performance traits was recorded from 27th to 46 weeks of age.Eggs were collected on a daily basis to study egg production rates, egg weight (g) and egg mass (g). A total of 45 eggs, comprising 5 eggs per treatment group were subjected to quality assessment (shape index, surface area, volume, egg weight, Haugh unit, yolk index and shell thickness) at the start (26 weeks) and at the end (46 weeks) of the experiment. Eggs were stored at 13-15°C and 70-80% relative humidity for seven days and then set in the hatchery at Avian Research and Training Centre (ARTC), University of Veterinary and Animal Sciences (UVAS), Lahore under standard condition for studying hatching traits (hatchability, fertility, early dead embryo and dead in shell percent). Collected data were statistically analyzed by two-way ANOVA technique followed by Tukey’s HSD test. Regarding morphometric traits at 16 weeks, drumstick length (12.24 vs. 11.65, 11.47cm; P = 0.0029) and circumference (8.63 vs. 7.23, 7.04 cm; P = 0.0029) of male birds was higher in NN chickens than BNN and RNN. Shank circumference was higher in BNN chickens followed by RNN and NN (P < 0.0001). Higher beak length was noted in RNN and BNN chickens than NN (3.28, 3.23 vs. 3.12 cm; P = 0.0008). Significantly higher wing spread was found in NN and BNN chicken as compared to RNN (9.02, 8.93 vs. 8.28 cm; P = 0.0002). In terms of housing systems, keel length was higher in semi-intensive and intensive birds as compared to free-range birds (10.66, 10.42 vs. 9.93 cm; P = < 0.0004). Higher drumstick length was observed in semi-intensive and free-range birds than intensive system (11.98, 11.93 vs. 11.46; P = 0.0468). Drumstick circumference (7.86, 7.65 vs. 7.38 cm; P = 0.0028) and beak length (3.26, 3.23 vs. 3.13 cm; P = 0.0043) were higher in free-range and intensive birds as compared to semi-intensive birds. In the interaction between genotypes and housing system, significant differences were observed regarding keel length (P < 0.0001), drumstick length (P = 0.0002), drumstick circumference (P < 0.0001), shank circumference (P < 0.0001), beak length (P < 0.0001) and wing spread (P = 0.0027). Regarding females, higher drumstick circumference was found in NN chicken as compared to RNN and BNN (8.07 vs. 6.65, 6.48 cm; P < 0.0001). Shank circumference was higher in BNN chicken followed by RNN and NN (P < 0.0001). Maximum wing spread was recorded in BNN and NN chickens than RNN (8.29, 8.21 vs. 7.55 cm; P = 0.0020). In terms of housing system, body length (57.79, 55.74 vs. 52.94 cm; P = 0.0005) and shank circumference (3.54, 3.52 vs. 3.25 cm; P = 0.0028) were maximum in semi-intensive and free-range birds than intensive system. Drumstick length was maximum in intensive birds than free-range and semi-intensive systems (11.66 vs. 10.47, 10.36 cm; P = 0.0007). Higher drumstick circumference was observed in free-range birds as compared to intensive and semi-intensive systems (7.42 vs. 7.03, 6.75 cm; P = 0.0017). Interactions were significant between genotypes and housing systems regarding body length (P = 0.0004), keel length (P = 0.0003), drumstick length (P = 0.0017), drumstick circumference (P < 0.0001), shank circumference (P < 0.0001), beak length (P = 0.0467) and wing spread (P = 0.0174). Regarding behavioral response, male birds under intensive system were more aggressive and showed more sitting (P < 0.0001) and standing (P < 0.0001) behaviors followed by semi-intensive and free-range systems (P < 0.0001). Birds under free-range system spent most of their time in feeding followed by semi-intensive and intensive systems (P < 0.0001). Jumping (P < 0.0001), running (P < 0.0001), walking (P < 0.0001) and wing flapping (P < 0.0001) behaviors were more pronounced in semi-intensive birds followed by free-range and intensive systems. Interactions were significant between genotypes and housing systems regarding aggressiveness (P < 0.0001), dust bathing (P < 0.0001), feeding (P < 0.0001), jumping (P < 0.0001), running (P < 0.0001), sitting (P < 0.0001), standing (P < 0.0001), walking (P < 0.0001) and wing flapping (P < 0.0001). Regarding females, RNN and BNN chicken revealed the highest running behavior than NN (6.66, 6.65 vs. 6.52%; P = 0.0466). In terms of housing systems, birds under intensive conditions were more aggressive along with spending more time in sitting (P < 0.0001) and standing (P < 0.0001) positions followed by semi-intensive and free-range systems (P < 0.0001). Birds under free-range system spent most of their time in feeding (P < 0.0001) and wing flapping (P < 0.0001) followed by semi-intensive and intensive housing systems. Jumping (P < 0.0001), running (P < 0.0001) and walking (P < 0.0001) were more pronounced in semi-intensive system followed by free-range and intensive system. Interactions were significant between genotypes and housing systems regarding aggressiveness (P < 0.0001), dust bathing (P < 0.0001), feeding (P < 0.0001), jumping (P < 0.0001), running (P < 0.0001), sitting (P < 0.0001), standing (P < 0.0001), walking (P < 0.0001) and wing flapping (P < 0.0001). Regarding carcass traits, RNN male chickens had the highest weight at slaughter at the age of 16 weeks (1491.12 vs. 1390.30, 1333.76g; P = 0.0009) and breast weight (158.35 vs. 128.26, 118.37g) as compared to BNN and NN. Liver weight (37.82 vs. 23.51, 23.02 g; P < 0.0001) and intestinal length (153.38 vs. 133.61, 130.59cm; P = 0.0009) were higher in NN chicken as compared to BNN and RNN. Higher gizzard weight was observed in NN and RNN chickens than BNN (25.03, 20.75 vs. 15.24g; P = 0.0001). Intestinal weight was higher in BNN and NN chickens than RNN (66.59, 63.80 vs. 52.01g; P = 0.0011). Drumstick weight was higher in BNN chickens than NN and RNN (142.74 vs. 122.57, 120.50 g; P = 0.0002). In terms of housing system, birds under intensive and semi-intensive systems had the highest weight at slaughter (1498.02, 1482.78 vs. 1234.37g; P < 0.0001) and dressed weight (829.78, 829.05 vs. 729.87g; P = 0.0007) than free-range birds. Highest carcass yield was found in free-range birds than semi-intensive and intensive systems (59.21 vs. 55.87, 55.35%; P = 0.0139). Liver weight (32.91 vs. 26.12, 25.32g; P = 0.0064) and intestinal weight (69.46 vs. 60.02, 52.92; P = 0.0005) were higher in semi-intensive birds as compared to free-range and intensive systems. Interaction were significant between genotypes and housing systems regarding weight at slaughter (P < 0.0001), dressed weight (P = 0.0001), carcass yield (P = 0.0162), liver weight (P < 0.0001), heart weight (P = 0.0285), gizzard weight (P = 0.0018), breast weight (P < 0.0001), intestinal weight (P < 0.0001), intestinal length (P = 0.0015), neck weight (P = 0.0003), wings weight (P = 0.0051), drumstick weight (P = 0.0003) and thigh weight (P = 0.0207). Regarding females, BNN and RNN chickens had significantly higher weight at slaughter (1175.39, 1168.32 vs. 1057.10g; P < 0.0001) and ribs and back weight (192.79, 189.37 vs. 167.99g; P < 0.0001) than NN. Dressed weight (P < 0.0001) and carcass yield (P < 0.0001) were higher in RNN chickens followed by BNN and NN. RNN chickens had the highest breast weight followed by BNN and NN (P < 0.0001). BNN chickens had the highest wings weight (P < 0.0001), drumstick weight (P < 0.0001) and thigh weight (P < 0.0001) followed by RNN and NN. In terms of housing systems, carcass yield was higher in semi-intensive system followed by free-range and intensive system (P < 0.0001). Intensive birds exhibited higher neck weight (45.11 vs. 35.61, 33.54g; P = 0.0002), wings weight (66.10 vs. 57.39, 54.06g; P < 0.0001), drumstick weight (124.93 vs. 93.41, 86.43g; P < 0.0001), thigh weight (132.85 vs. 107.68, 97.13 g; P < 0.0001) and ribs and back weight (209.66 vs. 174.42g; P < 0.0001) as compared to free-range and semi-intensive. Interactions were significant between genotypes and housing systems regarding weight at slaughter (P < 0.0001), dressed weight (P < 0.0001), carcass yield (P < 0.0001), liver weight (P = 0.0070), heart weight (P = 0.0021), gizzard weight (P < 0.0001), breast weight (P = 0.0219), intestinal weight (P = 0.0028), intestinal length (P = 0.0192), neck weight (P = 0.0009), wings weight (P = 0.0019), drumstick weight (P < 0.0001), thigh weight (P < 0.0001) and ribs and back weight (P < 0.0001). Regarding morphometric traits at 21 weeks of age, RNN and BNN male chickens had significantly higher body weight (1817.25, 1811.17 vs. 1616.05g; P = 0.0015) and shank circumference (4.25, 4.06 vs. 3.58cm; P = 0.0150) than NN. Drumstick circumference was higher in NN chicken than BNN and RNN (10.13 vs. 801, 8.00 g; P < 0.0001). In terms of housing systems, birds under intensive and semi-intensive systems had higher body weight than birds in free-range system (1849.97, 1774.89 vs. 1619.60g; P = 0.0012). Interactions were significant between genotypes and housing systems regarding body weight at 21 weeks of age (P = 0.0009) and drumstick circumference (P = 0.0039). Regarding females, BNN and RNN chickens had significantly higher body weight than NN (1456.22, 1425.17 vs. 1256.79g; P < 0.0001). Keel length was higher in NN and BNN chickens as compared to RNN (11.58, 10.89 vs. 10.04cm; P = 0.0002). Higher drumstick circumference was observed in NN chickens than BNN and RNN (9.82 vs. 7.03, 6.70cm; P < 0.0001). In terms of housing systems, birds reared in intensive system had the highest body weight followed by semi-intensive and free-range birds (P < 0.0001). Body length was maximum in semi-intensive and free-range birds than intensive system (66.76, 65.49 vs. 58.58cm; P < 0.0001). Interactions were significant between genotypes and housing systems in body weight at 21 weeks of age (P < 0.0001), body length (P < 0.0001), keel length (P < 0.0001) and drumstick circumference (P < 0.0001). Regarding serum chemistry, the highest cholesterol levels was observed in NN chickens, while, BNN showed the lowest value (143.87 vs. 127.11 mg/dL; P = 0.0123). Antibody titer against ND was significantly higher in RNN chickens and lower in BNN (5.10 vs. 4.77 HI titter; P = 0.0204). In terms of housing systems, birds reared under intensive system had the highest glucose level than semi-intensive and free-range systems (185.45 vs. 158.93, 138.43mg/dL; P = 0.0008). Antibody titer against IB was found higher in free-range birds followed by birds in semi-intensive and intensive systems (P = 0.0001). Interactions were significant between genotypes and housing systems glucose level (P = 0.0164), cholesterol (P = 0.0103) and antibody titer against IB (P = 0.0067). Regarding productive performance, BNN chickens had the highest body weight at 26 weeks (P < 0.0001) of age. Similarly, BNN chickens showed the highest hen day production % (P < 0.0001) and total egg mass (P < 0.0001) followed by RNN and NN. At the age of 46 weeks, BNN chickens were heavier than RNN and NN (1679.74 vs. 1484.45, 1391.25g; P = 0.0025). RNN and BNN chicken had significantly higher egg weight as compared to NN (53.16, 53.13 vs. 46.68g; P < 0.0001). In terms of housing systems, birds reared under intensive housing system had the highest body weight at 26 (P < 0.0001) and 46 (P < 0.0001) weeks followed by semi-intensive and free-range systems. Hen day production was higher in intensive birds than free-range and semi-intensive systems (59.70 vs. 57.80, 57.56%; P < 0.0001). Average egg weight (P < 0.0001) and total egg mass (P < 0.0001) were higher in intensive system followed by semi-intensive and free-range systems. Interactions were significant between genotypes and housing systems regarding body weight at 26 (P < 0.0001) and 46 weeks (P < 0.0001) of age. Production percent (P < 0.0001), egg weight (P < 0.0001) and egg mass (P = 0.0036) also showed significant differences in the interactions between genotypes and housing systems.Regarding egg characteristics (at 26 weeks), RNN and BNN chickens had significantly higher egg shape index (74.24, 73.98 vs. 71.91; P = 0.0002), egg surface area (58.24, 58.13 vs. 55.78cm2; P < 0.0001), egg volume (40.92, 40.81 vs. 38.37cm3; P < 0.0001), egg weight (44.82, 44.70 vs. 42.02g; P < 0.0001) and Haught unit score (78.84, 77.23 vs. 74.56; P = 0.0002) as compared to NN chicken’s. Shell thickness was the highest in NN chicken eggs the lowest in BNN (0.34 vs. 0.32mm; P = 0.0787) eggs. Interactions were significant between genotype and housing systems regarding egg shape index (P = 0.0053), egg surface area (P = 0.0057), egg volume (P = 0.0060), egg weight (P = 0.0060) and Haugh unit score (P = 0.0060).Regarding egg characteristics at 46 weeks of age, BNN and RNN chicken eggs had higher egg surface area (65.12, 64.75 vs. 59.59cm2; P < 0.0001) and volume (48.36, 47.97 vs. 42.35cm3; P < 0.0001) as compared to NN eggs. Egg weight (55.54, 52.97 vs. 46.39g; P < 0.0001), Haught unit score (82.44, 82.12 vs. 75.38; P < 0.0001) and yolk index (49.20, 48.00 vs. 37.47; P = 0.0004) were higher in RNN and BNN chickens than NN. Interactions were significant between genotypes and housing systems regarding egg surface area (P = 0.0002), egg volume (P = 0.0003), egg weight (P = 0.0003), Haugh unit score (P < 0.0001), yolk index (P = 0.0044) and shell thickness (P = 0.0012). Regarding hatching traits, RNN chickens had the highest hatchability followed by BNN and NN (P < 0.0001). Higher fertility was observed in RNN and BNN chickens than NN (87.43, 86.69 vs. 81.74%; P < 0.0001). In terms of housing systems, higher hatchability was noted in free-range birds followed by semi-intensive and intensive system (73.61 vs. 67.28 vs. 64.07%; P < 0.0001). Free-range birds showed the highest fertility than semi-intensive and intensive (88.42 vs. 84.71, 81.72 %; P < 0.0001). Interactions were significant between genotypes and housing systems regarding hatchability (P < 0.0001), fertility (P < 0.0001) and infertile eggs percent (P < 0.0001). On the basis of the above results it can be summed up that among different genotypes, an improvement was observed in RNN and BNN chickens in terms of body weight, morphological and carcass traits during growing phase as compared to NN chickens. During rearing period, RNN and BNN male chickens had higher body weight and shank length than NN; however, NN females chickens had the highest keel length, drumstick circumference and cholesterol levels. RNN females had the highest titers against ND. BNN chickens were better in terms of productive performance and egg characteristics as compared to RNN and NN. However, hatching traits were better in RNN chickens than BNN and NN. Regarding housing systems, male chickens reared under semi-intensive system had the maximum drumstick and keel length during growing stage than free-range and intensive birds. Female chickens reared under semi-intensive were better in terms of body and keel length and shank circumference as compared to the birds under free-range and intensive systems. Chickens (male as well as female) reared under semi-intensive system exhibited more pronounced explorative and maintenance behaviors than free-range and intensive systems. Chickens of both sexes reared under intensive system had better carcass traits as compared to semi-intensive and free-range birds. Glucose level was higher in female chicken under intensive as compared to the birds reared under semi-intensive and free-range systems; however, antibody titer against IB was higher in free-range birds followed by semi-intensive and intensive birds. During production stage, birds reared under intensive system showed better performance than semi-intensive and free-range production systems, however, hatching traits were better in free-range birds than semi-intensive and intensive birds. Key words: Housing system, chicken genotype, behavior, morphometric, serum chemistry, productive performance, egg quality, hatching traits." xml:lang="en_US