The aim of this study was to compare the performance, egg quality and economic aspects of laying hybrids of different genotypes in free-range system. In the study, three different laying genotypes (Lohmann Brown, Lohmann Sandy and ATAK-S genotype) were used. Each group consisted of four replicates and each replicate contained 20 hens. Egg production, broken–cracked egg ratio, egg weight, feed consumption, feed efficiency, and viability were determined as performance traits. Eggshell strength, Haugh unit, yolk color, and shell color were determined as egg quality traits. The costs of eggs were assessed for economic analysis. The Lohmann Sandy genotype produced more eggs than the Lohmann Brown genotype (p < 0.05). The ATAK-S genotype reached 50% egg production age sooner than other genotypes (p < 0.05). The Lohmann Sandy and Lohmann Brown genotypes produced fewer broken eggs and heavier eggs compared to the ATAK-S genotype (p < 0.05). The ATAK-S genotype consumed more feed than the Lohmann Sandy and Lohmann Brown genotypes (p < 0.05). The Lohmann Sandy and Lohmann Brown genotypes have better feed efficiency compared to the ATAK-S genotype (p < 0.05). Eggs from the Lohmann Sandy genotype exhibit greater resistance to breakage compared to those from other genotypes (p < 0.05). The highest quality of albumen was identified in the eggs of the Lohmann Brown genotype (p < 0.05). The yolk color of Lohmann Brown genotype eggs is darker than those of other genotypes (p < 0.05). The shell color of Lohmann genotype eggs is a darker brown compared to eggs of other genotypes (p < 0.05). The cheapest egg cost was determined from eggs produced from the Lohmann Sandy genotype (p < 0.05). According to the results obtained from our study, it would be more appropriate to prefer the Lohmann Sandy genotype in the free-range system.

In animal science, the nonlinear regression models for growth curve analysis ofgrowth patterns are separated into two groups called fixed and flexible according to their point of inflection. The aims of this study were to compare fixed and flexible growth functions and to determine the best fit model for the growth data of chukar partridges. With this aim, the growth data of partridges were modeled with widely used models, such as Gompertz, Logistic, Von Bertalanffy as well as the flexible functions, such as, Richards, Janoschek, Levakovich. So as to evaluate growth functions, the R2 (coefficient of determination), adjusted R2 (adjusted coefficient of determination), MSE (mean square error), AIC (Akaike’s information criterion) and BIC (Bayesian information criterion) goodness of fit criteria were used. It has been determined that the best fit model from the point of chukar partridge growth data according to mentioned goodness of fit criteria is Janoschek function which has a flexible structure. The Janoschek model is not only important because it has a higher number of parameters with biological meaning than the other functions (the mature weight and initial weight parameters), but also because it was not previously used in the modeling of the chukar partridge growth.

The aim of this study was to establish the effects of storage temperature on some egg quality in table eggs during 28 days. A total of 100 fresh eggs were obtained from laying hens (Nick chick) that were raised on a local commercial farm. All eggs were collected over a 24 h period. A total of 100 eggs randomly divided into 2 treatments (5 °C and 22 °C; 10 replicates each) with 50 eggs examined in each. Ten eggs from each group were analyzed for eggs weight loss, specific gravity, albumen height, Haugh unit, yolk index, and albumen pH after 0, 7, 14, 21 and 28 days of storage at 5 and 22 °C. All eggs were individually marked and weighed at the beginning of the experiment to calculate egg weight loss. The egg weight loss in eggs stored at 5 °C significantly (P<0.01) lower than the eggs stored at 22 °C group for the entire storage period. The eggs stored at 5 °C showed higher levels of specific gravity than eggs stored at 22 °C throughout 28 days of storage (P<0.01; P<0.05). The albumen height, Haugh unit, and yolk index of eggs stored at 5 °C was significantly (P<0.01) higher than that of eggs stored at 22 °C during the storage periods. The albumen pH of eggs stored at 5 °C was significantly (P<0.01) lower than that of eggs stored at 22 °C during storage period. The results indicated that the eggs stored at 5 °C are better off in terms of protecting quality compared to the eggs stored at 22 °C throughout 28 days of storage.

Incubation temperature is one of the important environmental factors that can induce epigenetic thermal adaptation of different physiological control systems. Thus, post hatch thermo tolerance ability of birds may be gained using these manipulations during different incubation periods. The current study was carried out to reveal the effects of temperature manipulations during early and late embryogenesis on weight of embryo and size of skeletal bilateral traits (face, wings, metatarsus, tibia, and femur) in broiler chicken embryos. One thousand commercial broiler eggs from 46 week old breeder flock were used in study. Treatments consisted of eggs incubated at 37.8°C and 55% relative humidity throughout (control; DG1), heated to 36.9°C and supplied 60% relative humidity for 6 hours daily from day 0 to 8 (DG2), heated to 36.9°C and supplied 60% relative humidity for 6 hours daily from day 10 to 18 (DG3), heated to 41°C and supplied 65% relative humidity for 3 hours daily from day 8 to 10 (DG4), and heated to 41°C and supplied 65% relative humidity for 3 hours daily from day 16 to 18 (DG5). Measurements of embryo weight and bilateral traits were obtained at 20 day of incubation and at hatch (at day 21). It was determined that the live weights of embryo and chick were affected significantly by treatment; DG3 group has shown higher mean values than the other treatment groups (P<0.05). There were differences in lengths of femur, tibia and metatarsus among treatment groups at hatch. Particularly, the high incubator temperatures at the second half of incubation accelerated growth of body and bone in embryos. These consequences of the treatments performed at different temperatures and times indicate that the different metabolic shifts realized by the embryos.