The rapidly growing population of the world has increased the demand for cheap and affordable chicken meat, eggs, and poultry products. Pomaah et al. (2023) reported that the demand for poultry products have increased tremendously due to increasing levels of income and standard of living. This has increased the search for the production of other alternative poultry species such as quails (Ozkan et al., 2024). Quails are one of the fastest-growing alternative poultry species and there are various genotypes or strains of quails worldwide. These birds are normally characterized by their feather color or country of origin. By plumage color, the most common are brown, black, grey, and golden quails, and by country of origin, they are classified as Japanese quails, European quails, Pharaoh quails, and Manchurian Golden breeds. However, the most widely known and most commonly used for experimental research is the Japanese quail (Coturnix japonica).

The commercial production of Japanese quails (Coturnix japonica) as an alternative poultry specie is gaining a significant interest compared to the production of other alternative poultry species (Abdallah et al., 2024). Japanese quails have attracted attention as an important species due to the unique flavour of their meat and eggs (Kayang et al., 2004). The small body size, low maintenance cost, high egg production, short generation interval, and disease resistance of the Japanese quails make these birds excellent laboratory animals (Baumgartner, 1994; Yalcin et al., 1995). Quail production is relatively easy and their housing requirements are less complex compared to the housing requirements of chickens (Capitan, 2003; Lambio, 2010). Indeed, Bagh et al. (2016) reported that in India, the Japanese quail is a promising poultry species for rural farmers due to its minimal capital and management requirements.

In terms of size, Japanese quails are the smallest farmed poultry species (Panda & Singh, 1990) and have become highly important for their eggs and meat (Baumgartner, 1994; Dahouda et al., 2013). Quails are characterised by faster growth, and rapid reproduction, coupled with a higher efficiency in converting feed into eggs and meat (Randall & Bolla, 2008).

Eggs are an important source of nutrients (Kurşun et al. 2024a) and it has been reported that eggs of Japanese quails are rich in minerals, vitamins, and antioxidants with a nutritional value 3-4 times higher than chicken eggs (Lalwani, 2011; Tunsaringkarn et al., 2013). Additionally, a comparative analysis by Ioniţă et al. (2008) revealed that the meat of quails has the highest amount of protein and the lowest amount of calories compared to duck and broiler meat. According to Vali (2008), quail meat is lean and its low cholesterol content makes it a superior economic source of animal protein.

Similar to broiler chickens and layer hens, the housing system (Roshdy et al., 2010) and the strain of the quail are some of the most important factors affecting growth and welfare performance as well as carcass and meat quality trait of quails. For instance, Islam et al. (2014) identified the effect of quail genotype on body weight at hatch, highest and lowest in Japanese quail genotype and black quail genotype, respectively. Uçar et al. (2024) also identified lower body weight in quails housed in litter systems compared to those housed in either conventional or enriched cages. In addition, better feed conversion efficiency in brown quails at 2 wk of age and in white quails at 6 wk of age were identified (Tawfeq, 2024).

Therefore, this research investigated the effect of housing system and strain on growth performance and carcass trait of quails.

The effect of the strain on hatching weight and post-hatch performance trait is given in Table 2. While the strain had no significant effect on body weight at hatch and at 5 wk of age (P>0.05), the brown quails had superior body weight than the golden quails between 1 wk and 4 wk of age (P≤0.05). However, the body weight gain did not statistically differ between the strains throughout the experimental period (P>0.05).

Additionally, the feed intake at 1 wk, 2 wk, 3 wk and 5 wk of age did not statistically differ between the strains (P>0.05) however, at 4 wk of age, the golden quails had a significantly higher feed intake than the brown quails (P≤0.05). Similarly, between 1 wk and 4 wk of age, the feed conversion ratio did not significantly vary between the strains (P>0.05) however, the feed conversion efficiency of the brown quails was better than that of the golden quails at 5 wk of age (P≤0.05).

The effects of the housing systems on body weight, body weight gain, feed intake, and feed conversion efficiency are given in Table 3. The body weight was significantly higher in quails reared in cages between 1 wk and 5 wk of age (P≤0.05). The least body weight throughout the experimental period was identified in the quails housed in slatted floors. While the body weight gain was statistically higher in quails reared in cages at 3 wk and 5 wk of age (P≤0.05), the quails housed in slatted floors had the highest significant body weight gain at 4 wk of age (P≤0.05). Feed intake was significantly higher in quails reared in the litter system between 1 wk and 2 wk of age (P≤0.05) however, between 3 wk and 5wk of age, the quails housed in cages had the statistically highest feed intake (P≤0.05). Additionally, feed conversion efficiency was significantly better in quails housed in slatted floors and litter system between 3 wk and 4 wk of age, respectively (P≤0.05).

The interaction effect of the strain and the housing system is presented in Table 4. It was identified that the interaction effect of the housing system and the strain had no significant effect on the body weight, body weight gain, feed intake, and feed conversion ratio (P>0.05).

The effect of housing systems and strains on carcass traits and internal organ weights are presented in Table 5. The dressing percentage was significantly higher in golden quails than in brown quails (P≤0.05) however, the heart weight was significantly higher in brown than in golden quails (P≤0.05). Additionally, carcass weight was significantly higher in quails housed in cages than in quails housed in other production systems (P≤0.05).

In the current study, the hatching weight did not significantly differ between the quail strains however, the post-hatch body weight during the rearing period was higher in brown quails than in golden quails. In line with the findings of the current study, other authors have also identified no significant effect of genotype on the hatching weight between brown and golden quails or other quail genotypes (white and grey) (Bagh et al., 2016; Nasr et al., 2017; Kursun, 2022) however, Islam et al. (2014) identified the effect of quail genotype on hatching weight, highest in Japanese quail genotype and lowest in black quail genotype. The higher significant body weight observed in the brown quails between 1 wk and 4 wk of age is a direct reflection of their faster growth rate and development. In line with the findings of the present study, different authors (Al-Kafajy et al., 2018; Chatoo & Al-Barzinji, 2022; Kursun, 2022) have also identified higher body weight in brown quails than in golden quails or quails of other strains. However, Nasr et al. (2017) reported that at 2, 4, and 6 wk of age brown quails had lower body weight compared to other quail strains.

In the present study, the body weight gain did not significantly differ between the strains throughout the experimental period. This contradicts the findings of other studies (Hassan and Abd-Alsattar, 2016; Chatoo & Al-Barzinji, 2022; Kirrella et al., 2023) that have reported higher significant body weight gain in brown quails than in other quail strains. The differences in the results could be related to the housing systems used in the various studies, nutrition, and the performance of the other quail strains that were compared to the brown and golden quails.

The present study was conducted in winter and during the entire third week of the study there was an electric problem in the poultry unit where the quails were reared. Due to this reason, there were no heating systems which severely affected the performance, especially the feed intake of the quails on that week. However, the golden quails had better feed intake at 4 wk of age than the brown quails. Poultry birds eat to meet their energy requirements and it may be possible that the golden quails had higher energy requirements for maintenance and growth (compensatory feed intake) after the heating system was restored at 4 wk. Contrary to the findings of the current study, Kursun (2022) identified a significantly higher total (0-5wk) feed intake in brown quails than in golden quails. Chimezie et al. (2018) also reported no significant difference in feed intake between brown and other quail strains, however, Kirrella et al. (2023) reported higher total feed intake in brown quails compared to quails of other strains. The age of quails, housing system, stocking density, and the environmental management may have accounted for the difference between the results reported by the various authors.

Feed conversion efficiency was better in brown quails than in golden quails at 5 wk of age. The brown quails might have been characterised by a better digestive system or gut health, leading to a better conversion efficiency of feed into body mass however, Kursun (2022) identified better feed conversion efficiency in golden than in brown quails.

In the current study, the body weight of the quails housed in cages was significantly higher than that of quails housed in the other production systems between 1 wk and 5 wk of age. This confirms the findings of previous studies (Meneeh and Fouda, 1992; Fouzder et al., 1999; El-Sagheer et al., 2012; Kayastha et al., 2012; Razee et al., 2016; Badawi, 2017; Gözet et al., 2019) that have identified higher body weight in quails housed in cages compared to those housed in other production systems (floor, cage, slatted floor). The higher body weight in the quails housed in the cage system is a direct reflection of the high feed intake among quails in this group. Additionally, it could be possible that the quails housed in the cage system spent less energy due to the limited space for movement which in turn led to the conversion of most of the energy in feed into fat in the adipose tissue. This event could have also contributed to the higher overall body weight identified in the quails housed in the cage system. Furthermore, the quails in the cage system had no advantage of expressing natural behaviours, which might have caused them to spend more time expressing feeding behaviour than the quails in the other housing systems (with some opportunities for expressing other more natural and playful behaviours). However, EL-Sheikh et al. (2016) and Muhammad & Mirza (2019) reported higher body weight in quails housed in litter system than in quails housed in cages. Similarly, Gözet et al. (2019) also identified higher body weight in quails housed in litter system at 1 wk of age than in quails housed in cages. The differences between the results of the various studies may be related to the strain, age, and stocking density.

The body weight gain in the present study was significantly higher in quails housed in cages at 3 wk and 5 wk of age, however, the quails housed in the slatted floor had the highest body weight gain at 4 wk. The higher body weight gain in the quails housed in cages at 3 wk and 5 wk could be attributed to their faster growth rate and development. Additionally, the higher body weight gain observed in the quails housed in the slatted floor system could be attributed to compensatory growth due to the electrical management problems of the previous week. It is therefore speculated that the quails housed in the slatted floors were the most affected by the electrical problem and therefore converted most of the energy in feed into body weight to compensate for the previous loss after normal housing conditions were restored. In line with both the findings of the current study, significantly higher body weight gain in quails housed in non-cage housing systems as well as in cages has been identified by several authors (Kayastha et al., 2012; Badawi, 2017; Alindekon et al., 2019).

Feed intake was significantly higher in quails housed in litter system between 1 wk and 2 wk of age however, the quails reared in cages had the highest feed intake between 3 wk and 5 wk of age. The higher feed intake between 1 and 2 wk in quails reared in the litter system may be attributed to the fact that birds reared on wood shavings and in non-cage rearing systems are stress-free and easily acclimatized to their environment which could lead to a rapid return to the expression of normal behaviour such as feeding or foraging. However, the higher feed consumption in quails housed in cages between 3 wk and 5 wk of age may be related to activation of higher feeding behaviour to compensate for lost feed consumption during the early production cycle. Additionally, birds in cages do not have enough space or enrichment to explore or to express most of their natural behaviours and therefore may spend most of their time feeding or engaging in feeding behaviour. Similar to findings of the current study, different authors have also identified higher feed intake in quails housed in either cages or litter systems throughout the production cycle (Kayastha et al., 2012; Alindekon et al., 2019; Gözet et al., 2019; Muhammad & Mirza, 2019).

In the current study, better feed conversion efficiency between 3 wk and 4 wk of age was identified in quails housed in non-cage production systems (litter system and slatted floors) than in quails housed in cages. Birds in cages are identified with poor welfare due to stress, which has a profound negative effect on their performance (Kursun et al., 2024b). This might account for the poorer feed conversion efficiency observed in the quails housed in cages. El-Sagheer et al. (2012) and EL-Sheikh et al. (2016) also identified a better feed conversion ratio in quails housed in non-cage housing systems than in quails housed in cages.

The similar carcass weight between the strains in the current study confirms the findings of Chatoo & Al-Barzinji (2022) and Kursun (2022), who also reported identical carcass weight between quail strains. In addition, Kursun (2022) identified a higher dressing percentage in golden quails, which is in line with the findings of the present study. The higher dressing percentage in golden quails may be due to their higher carcass weight compared to brown quails. It is possible that the brown quails had a higher percentage of abdominal fat resulting in higher live weight but lower carcass weight. Additionally, it could also be possible that at the slaughter age, growth and development were still continuing in golden quails however, brown quails may have reached their peak growth and developmental stage earlier before the slaughter age.

The heart weight was higher in brown quails than in golden quails in the present study and this may be due to the rapid growth and development of this strain. Although not significantly different, Kursun (2022) also identified a higher heart weight in brown quails than in golden quails.

In line with the findings of the current study, Badawi (2017) also reported no significant effect of the production system on the weight of internal organs (heart, liver, and gizzard). Additionally, the carcass weight was higher in quails housed in cages than in quails housed in other production systems. This observation is a direct reflection of the higher body weight identified in quails housed in cages throughout the experimental period. Our findings contradict the results of Gözet et al. (2019) and Muhammad & Mirza (2019), who reported a higher carcass weight in quails housed in a litter system and free-range than in quails housed in cages.

The overall performance of quails housed in cages in terms of body weight, body weight gain, carcass weight, and feed intake were better than that of quails housed in other production systems. Growth performance was poorest in the quails housed in the slatted floors. Additionally, brown quails had superiority in terms of body weight, body weight gain, and feed conversion ratio than golden quails. It was therefore concluded that brown and golden quails could be reared in cages or litter systems without any negative effect on growth performance and carcass traits. However, because most of the research focused on cages, litter systems, or free-range systems, it is recommended that subsequent research should be conducted to investigate the effect of indoor systems with slatted floors on quail performance.