## 4 Discussion  
In Europe, there is increased protection of animal welfare. However, in many developing countries and regions, stalls are still used to raise sows in gestation units. Most studies focus on the design of precision feeding equipment in group housing, but few have considered the problems that need to be overcome for precision feeding in stall housing systems: (1) conventional feeders are prone to over-adjustment leading to large errors in the delivery of feed; (2) there are many feeders installed in the stalls but a lack of efficient hierarchical control; and (3) with high levels of bio-security, the production area and information department are isolated from each other, leading to the slow transfer of production data. In this research, we conducted a feed delivery experiment using 60 ESFs installed at various positions along the feed transmission line. The speed at which each ESF delivered feed was measured. The data revealed a central tendency between 1350 g and 1450 g, with  
Figure 11: (**a**) Relationship between TR and concurrent threads and (**b**) relationship between average IoT_RT and concurrent threads. an average value of 1395 g and a coefficient of variation at 1.55%. Notably, our analysis did not reveal discernible relationship between feed abrasion and delivery speed. To evaluate the accuracy of feed delivery, we based our calculations on an average speed of 1395 g per 30 revolutions, and we investigated the relative error between the actual delivered feed mass and the expected delivery mass. Our findings consistently demonstrated that the relative error for all 60 ESFs remained within the range of \(\pm\)2.94%, with a coefficient of variation of less than 1.84% across different expected feed weights. It is worth noting that [PERSON] et al. [43] conducted a similar experiment, but their focus was on a single ESF, resulting in a maximum relative error of +2%. Given our emphasis on the collective performance of multiple ESFs, the \(\pm\)2.94% range is deemed an acceptable indicator. The structure of the feeding auger stands out as the optimal choice for the widespread implementation of ESFs, as it ensures uniform and consistent feeding performance. In the scientific literature, there is a conspicuous absence of data communication of ESFs in large-scale gestation units using stalls. In a study involving the use of the feeding station Nedap Velos, conducted by [PERSON] et al. [44], a significant challenge arose--feed intake data had to be manually extracted on a daily basis due to the lack of long-term data storage capabilities. Additionally, the study reported instances of lost RFID tags in group housing, resulting in potential inaccuracies in data recording. In our system, each ESF is dedicated to a specific sow, which addressed the issues mentioned above. Furthermore, through the CAN, ESF data are seamlessly transmitted to the Center Controller, facilitating efficient data collection and distribution. This not only enhances data management but also leads to significant cost savings in terms of labor. Sow production management can be categorized into two approaches: normal management and batch flow management [45]. In batch flow management, timed artificial insemination and the administration of various hormones are employed to regulate the timing of estrus, ovulation, and farrowing [46]. However, normal management necessitates individualized care for each sow. To facilitate this, we designed the PDA for the convenient adjustment of individual ESFs. The PDA features an intuitive user interface that provides essential functionalities for pig farming, effectively reducing the cognitive burden on breeders by minimizing comprehension costs. Through a wired connection with ESFs, close contact between breeders and ESFs is prohibited to ensure bio-safety. In practical applications, maintaining the power of the ESF's WIFI module at levels greater than \(-\)70 dbm within an appropriate operating distance is advisable to ensure a stable communication effect.