The average birth weight and body weight at different ages of purebreds and crossbreds were shown in Table 1. The significantly prominent birth weight (29.58 g) was found in the FC group (
p<0.05), followed by FAH (28.13 g), CF (27.09 g) and CHE (26.78 g), respectively. These results corresponded to Thai native black-bone chickens, namely Chee Fah
(Morathop et al., 2005) and Fah Luang
(Intarachote et al., 2003; Intharachote et al., 2005) and other Thai indigenous chickens (
Penmas, 2005;
Leotaragul et al., 2015; Sungkhapreecha et al., 2015; Molee et al., 2018). While, some studies revealed higher birth weights
(Suayroop et al., 2012; Siripanya et al., 2013; Patra et al., 2018), which might be due to they were genetically improved for productive performance. However, the results in the present study agreed with some previous studies of native and crossbred chickens in the other countries (
Van Marle-Köster and Casey, 2001;
Malago and Baitilwake, 2009).
Correspondingly, FC had the highest BW during 4- to 20-week of age, whereas, CHE showed the lowest values (
p<0.05). Over a period of 20 weeks, our investigation confirmed that crossbred groups had significantly higher values of BW than purebreds (
p<0.05). A possible reason might be heterosis effect that caused crossbred groups have better performances than purebreds (
Falconer and Mackay 1996). The average 20-week BW of CHE and FAH were resembling with Nigerian native chicken (
Sola-Ojo et al., 2011). Similarly, crossbred CF chickens’ weight was consistent with the study of
Khawaja et al., (2013), who reported that the BW of 2-way and 3-way crossbred chickens were 1236.50 and 1288.73 g, respectively. However, some various weights of 20-week of age were published
(Mosaad et al., 2010; Osei-Amponsah et al., 2012; Khadda et al., 2017; Sarma et al., 2018). The contrary could be explained by different genetic background, age and maturity, sex, environment and farm management in each study, which the main effect influenced quantitative traits.
Table 2 represents the comparison of productive performance among chickens separated by genetic groups. The significant difference of the FI during 20-week period was observed (
p<0.05), CHE chickens consumed less feed, while the largest was found in FC group. Considering the average daily feed intake, the range of 48.72 to 50.76 was found in our chickens (data not shown). FI values in this study were lower than some previous publications
(Kittichonthawat et al., 2003; Suayroop et al., 2012; Khawaja et al., 2013). Several authors reported that the various results of feed intake were a response of the breed differences (
Van Marle-Köster and Casey, 2001;
Castellini et al., 2002; Azharul et al., 2005; Castellini et al., 2016). Additionally, another possible reason might be surgical caponization, which capons consumed feed more than intact chickens during 18 to 28 weeks of age (
Lin and Hsu, 2002).
The FC crossbreds showed more favorable FCR (5.44) than CF group (5.58), furthermore, they had significantly better value than both of purebred chickens (
p<0.05; Table 2). Considering purebred groups, the average FCR of FAH chickens was significantly lower than CHE (5.61 vs. 5.65;
p<0.05). Our investigation correlates with the previous literature, which reported that FCR of crossbred native chickens tended to predominate over purebred natives (
Azharul et al., 2005). On the contrary, some studies revealed that no significant difference was found between purebred and crossbred native chickens
(Kittichonthawat et al., 2003; Siripanya et al., 2013). However, the high FCR range (11.1 to 13.9) was reported in the Northwest Ethiopian indigenous chickens during 0 to 22 weeks old
(Hassen et al., 2006). The different FCR values were published due to FCR is considered as a quantitative and complex process trait which is influenced by many factors, such as animal behavior, level of production, appetite, including interaction between them
(Hassen et al., 2006).
In view of ADG, FC chickens significantly grew faster than the others (
p<0.05) with 9.34 g/day (Table 2). The current findings were similar to Pradu Hang Dam chickens (
Penmas, 2005), Black Hmong, Black Chinese, Brown Hmong and crossbred Black Hmong × Pradu Hang Dam chickens
(Sungkhapreecha et al., 2015) However, some studies revealed greater ADG with the average varied from 16.1 to 54.5 g/day
(Castellini et al., 2002; Chen et al., 2014; Leotaragul et al., 2015; Castellini et al., 2016). Due to the factors affect ADG are not only genetic, but also the age of the chicken. According to those publications, they set the experiment on chickens during 0 to 12 weeks old, while the present study accounted for 0-to 20-week of age. The disagreement was explained by
Mosaad et al., (2010), who reported that the growth rate of indigenous chickens reached a peak during the first 12-week of age and decrease during the age of 12 to 20 weeks.
There was no significant difference in the percentage of viability among our chickens (
p>0.05; Table 2). However, our percentages of viability fell into the range of previous studies (60.20 to 98.46%;
Kittichonthawat et al., 2003;
Hassen et al., 2006; Khawaja et al., 2013). The environmental factors such as disease, accident and farm management could reduce the percentage of viability, even if it has genetically enhanced to a maximum level
(Hassen et al., 2006; Khawaja et al., 2013).
