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Effects of egg storage length and orientation on hatching traits and spread of hatch were determined in Transylvanian naked neck chickens. Eggs (n = 640) stored in a cold room (16 ± 1.5°C, 75 ± 1.5% RH) in batches of 160 eggs each, for 1, 3, 5 or 7 days were used.Half of each batch was stored with a broad end up (BEU) and the other in a narrow end up (NEU). Eggs were incubated in a two-stage incubator (37.5°C, 64% RH). Storage length caused a significant increase in egg weight loss (EWL; p < 0.001). Egg fertility (FERT) was significantly lower in 7 days than in 1, 3 and 5 days stored eggs (p < 0001). Dead in shell (DIS) was lower (p < 0.001) in 1-day storage than in other lengths (p < 0.001). Hatchability of total (HSE) and fertile eggs (HFE) decreased (p > 0.001) gradually from 1 to 7 days, though 3 and 5 days were found to be similar. Hatching commenced earlier (p = 0.055) in 5 days than 1-day storage. Incubation time at 100% hatch, hatch window and spread of hatch were not (p > 0.05) affected by storage length. At the end of the hatch, longer storage than 1 day caused 45, 45 and 15 min/day delay in hatching for 3, 5 and 7 days storage respectively. The chicks from 3 days storage (17.3 cm) were longer (p = 0.05) than those from 5 (17.1 cm) and 7 days groups (17.1 cm). Higher DIG and DIS but lower HSE and HFE (p < 0.05) were recorded in BEU than in NEU orientation. Earlier commencement of hatch (CH) was recorded in BEU than in NEU eggs. There were significant (p < 0.05) interactions between storage length and orientation in FERT, DIG, HSE, HFE, CH and hatch windows. To achieve HFE up to 70%, eggs could be stored for up to 7 days in NUE orientation but should not exceed 3 days in BEU orientation.

In bridging the knowledge gap on stress physiology of Nigerian indigenous chickens, this study investigated the effect of exogenous corticosterone (eCORT) as stress inducing agent on the testicular function and mating behavior of Nigerian indigenous cocks. Twenty-four (24) cocks and one hundred and forty four (144) hens (mating ratio of 1 cock: 6 hens) were grouped into four and assigned to each of the four eCORT treatments (0, 2, 4 and 6 mgeCORT/KgBW) daily for 14 days. Semen samples were collected on days 0, 7 and 14 and analyzed for semen volume (SV), progressive sperm motility (PSM), membrane integrity (MI) and sperm abnormality (SA). Mating behaviors were monitored on days 3, 5 and 8. Blood samples, for hormonal (Luteinizing Hormone (LH), Follicle Stimulating Hormone (FSH) Testosterone (TEST) and stress analysis (heterophil/lymphocyte ratio, H/L) were collected from brachial vein on days 7 and 14. On day 15, cocks were euthanized and testes harvested for histomorphometry. Data were analyzed using multivariate analysis, one-way ANOVA and Kruskal-Wallis tests all in SPSS 23. Administration of 4 mgeCORT/KgBW declined (P<0.05) PSM while 4 mgeCORT/KgBW and 6 mgeCORT/KgBW cocks had reduced (P<0.05) SV and MI with increased SA. Compared to baseline values, progressive sperm motility of cocks administered 6 mgeCORT for 7 and 14 days decreased (P<0.05) by 57.5% and 52.4%, respectively. Exogenous CORT had no significant (P>0.05) influence on the mating behaviors, H/L ratio, FSH and TEST. However, 2 mgeCORT/KgBW enhanced LH levels. Administration of eCORT did not affect the testicular epithelial height and seminiferous tubular diameter. In conclusion, optimal stress induced by eCORT impaired semen quality but with less impact on reproductive hormones, H/L and mating behaviors of intensively raised Nigerian indigenous cocks.

Cryopreservation is a viable reproductive technique but still have detrimental consequences on sperm quality and fertility. This study compared the sperm cryotolerance among different breeds of chickens in hot humid environments. Semen samples were collected from thirty (30) cocks comprising 10 Funaab alpha normal feathers, Arbo acre and dominant black. The semen was analyzed for acrosome integrity, membrane integrity, seminal leukocyte, Live/dead, sperm abnormality, MDA concentration and sperm motility. Breed differences (p < 0.01) were observed in Acrosome integrity, seminal leukocyte, live/dead ratio, sperm abnormal midpiece and sperm abnormal tail. The stepwise discriminant analysis revealed that live/dead, MDA, Abnormal midpiece, Leukocyte, Acrosome, Abnormal head and sperm motility are discriminant variables that can effectively differentiate the three breeds of chickens with Live/dead, MDA and Leukocyte having highly significant (P < 0.0001) discriminatory power. The study obtained two canonical variables accounting for 66.94% and 33.06% of the total variation respectively. The three breeds of chicken were differentiated by linear discriminant functions. 56.67% of Funaab Alpha chicken, 67.78% of Arbo acre and 47.78% of Dominant black chicken were accurately assigned into their breeds while the longest Mahalanobis distance was found between Arbor Acre and Funaab Alpha chicken. The discriminant functions obtained in this study could help differentiate these three breeds of chicken that are suitable for artificial insemination in humid tropics using their post-thaw semen quality.