Furthermore, an increase in latency to exit the Y-maze was also observed at 15 weeks of age, even though the Ymaze remained the same size for all three time points. We suggest that the birds may have been less likely to exit the Y-maze and cross the visual cliff at the intermediate time points due to increased fearfulness. Tonic immobility is a catatonic-like state induced by a short period of physical restraint, typically after placing a chicken on their back and briefly holding them in place . Tonic immobility has been found to relate to fearfulness, with longer periods of tonic immobility being associated with other fear-inducing situations such as novel environment or loud noise . Previous studies on the development of fear in chickens have found that tonic immobility is longer at the onset of sexual maturity . Campo & Carnicer and Ghareeb et al. tested laying hens at a range of ages on a tonic immobility task. Campo and Carnicer found that tonic immobility increased until its maximum duration at 16 weeks of age, before declining and then slowly increasing after 24 weeks. Similarly, Ghareeb et al. found that tonic immobility reached its maximum duration at 20 weeks of age before decreasing in duration for each subsequent age tested. These results suggest that fearfulness in laying hens is elevated around the onset of lay. The differences we observed in latency to complete the depth perception tests are potentially due to increased age-related fearfulness. Heightened levels of fear in hens may result in decreased exploratory behavior in a novel environment .
Increased age-related fearfulness resulting in decreased exploratory behavior would explain the longer latencies we observed on the Y-maze and visual cliff task during the intermediate time point as well as the decreased frequency in crossing the visual cliff at this time point. However, large square plant pots this is only speculation as we did not measure general fearfulness of the birds. Exploring this relationship in future studies is needed to better understand the relationship between age-related fearfulness, exploratory behavior, and latency to complete cognitive tasks. It is important for further studies to investigate the impacts of increased age-related fearfulness on the transition into a novel housing system. The onset of sexual maturity is both the time period when laying hens are transferred to their adult housing systems and the time at which age-related fearfulness may be elevated. The potential effects of this fearfulness on exploratory behaviors in a novel environment and willingness to use novel structures at this age could be crucial to better understanding that transition from rearing to adult housing in laying hens. At 16 week old birds looked down significantly more over the visual cliff than 8 and 30 week old birds. Additionally, FLOOR birds looked down significantly more often than MULTI and SINGLE birds across all time points. Looking time is a measure used in pre-verbal infants and non-human animals to evaluate attentional bias, with an increase in looking time often being associated with novelty, vigilance directed at a threat, or violation of expectations .
In the present study, looking frequency instead of duration was used due to the tendency of the hens to orient their head down and then back up very quickly and frequently. This increased frequency in looking down over the visual cliff could be attributed to the depth violating their expectations or attentional bias towards the novelty of a cliff. Depth would be novel and potentially unexpected for FLOOR birds who had never previously encountered a cliff, perch over 30 cm high, or platform. As previously discussed, it is likely the birds were experiencing greater fearfulness at the intermediate time points. Due to this and previous studies using looking time as a measure of hyper-vigilance and attention , the increased frequency of looking down at this time point may have been related to increased fearfulness, attention, and caution towards the cliff.By investigating how hens perceive their environment we can make more informed decisions about improved rearing practices. Our results do not suggest that floor rearing of pullets has an impact on the development of proper depth perception, however differences in behavior were observed. The FLOOR birds were more hesitant to cross from a perch to a platform over the visual cliff, with longer latencies and decreased likelihood of crossing when compared to SINGLE and MULTI birds. This suggests that floor reared birds are more hesitant to utilize vertical structures just prior to being transitioned into their adult housing. This could have implications for the welfare of floor reared birds transitioned into multi-tiered aviaries.
Hens are highly motivated to use nest boxes and may show signs of frustration when access to these recourses are inhibited, suggesting the importance of nest boxes for hens and their welfare . Hesitation and avoidance of using the system could prevent hens from taking full advantage of the benefits provided in multi-tiered aviaries, such as nest boxes. This is supported by previous findings that, when compared to aviary-reared birds, floor reared birds are more likely to lay floor eggs and less likely to utilize resources located on raised platforms . In order to best prepare pullets for multi-tiered aviaries, birds should be provisioned at a young age with vertical structures, such as perches, ramps, and platforms.It is clear from previous studies that aspects of spatial cognition, including spatial memory and navigation, are impacted by early experience with vertical structures . However, the current study presents evidence that a crucial aspect of spatial cognition needed for gauging flight and landing distance, depth perception, is not affected by differences in vertical complexity of the rearing environment. The results of this study show that pullets reared in more vertically complex rearing systems cross from a perch to a platform more readily than those reared on the floor, however this discrepancy disappeared by the final time point. This suggests that floor reared birds are more hesitant to cross from a perch to a platform and that this effect is reversed after exposure to a vertically complex environment. Future research is needed to determine how longit takes for the reversal to occur and the degree to which floor reared birds will avoid using or transitioning between vertical structures. This hesitation and avoidance of vertical structures could have implications for improved rearing practices for pullets destined for multi-tiered aviary systems.Alternative agriculture – or agriculture that is alternative to mainstream, industrial forms of agriculture – existed prior to the 1950s as the dominant form of agriculture worldwide . In the United States, alternative agriculture casts a wide umbrella of terms, and can include organic farming, sustainable farming, agroecological farming, diversified farming, indigenous agriculture, biodynamic farming, urban farming, conservation or regenerative agriculture, and/or permaculture – to name a few. Regardless of its form, a key feature of alternative agriculture is that it is inherently knowledge intensive . Farming alternatively requires that farmers support a knowledge infrastructure that is multi-faceted and context-specific, often informed by scientists, researchers, policymakers, government, large square planting pots and/or extension agents. Farmers who practice alternative agriculture amass a wealth and depth of knowledge that integrates multiple ways of knowing and that reflects diverse knowledge systems for thinking about evidence; perhaps most importantly, farming alternatively is based in practice and necessitates deep knowledge of the local . Farmer knowledge is thus an essential component of practicing alternative agriculture. Despite the central role of farmer knowledge in alternative agriculture, this knowledge has long been overlooked in US agriculture – considered “informal” knowledge – and therefore infrequently recorded or incorporated within the scientific literature . Since the 1950s with the introduction of chemical-based, input-intensive industrial agriculture, farming in the US experienced an increase in knowledge standardization, whereby technical farming knowledge has become highly transferable, scalable, and independent of its local social or environmental context . The simultaneous consolidation of land ownership and shift toward widespread deskilling among farmers and farmworkers in industrial agriculture have also minimized the knowledge infrastructure, while increasing the technological infrastructure, required to farm .
As a consequence, farmer knowledge of alternative agriculture in the US has declined and has also become increasingly undervalued . If these trends continue, farmer knowledge of alternative agriculture in the US may considerably decrease, or in some cases, become permanently lost . Given that the role of farmer knowledge in alternative agriculture research in the US is currently overlooked, it is essential that we begin to 1) understand the key features of farmer knowledge; 2) understand the substance of farmer knowledge; and 3) systematically document farmer knowledge in specific local contexts. Understanding the substance of farmer knowledge serves as a first step to sustain this essential knowledge base in practice; it is equally critical to document the particularities of farmer knowledge in local contexts. Farmer knowledge may provide an essential knowledge base that can inform and extend scientific research in alternative agriculture, and also potentially inform and extend the knowledge base of contemporaneous and future generations of farmers, policymakers, and agricultural industry experts.Moving forward, there is a need to elevate the importance and legitimacy of farmer knowledge across disciplines within agriculture such that farmer knowledge is considered a valued knowledge base within alternative agriculture research, policy, and beyond . While other studies attempt to integrate the artificial binary between “formal” and “informal,” or “expert” and “non-expert” knowledge and view the two forms of knowledge as complementary , in this paper we maintain that farmer knowledge represents a systematic way of knowing, and therefore warrants formal, standalone documentation and incorporation within the scientific literature .Farmer knowledge is a type of local knowledge . As such, farmer knowledge, especially in the context of alternative agriculture, becomes relevant when linked to a particular local context . Broadly defined, local knowledge involves dynamic processes and complex systems of experiences, practices, and skills developed and sustained by people in their environmental and socioeconomic realties , which means that local knowledge is place-based and dynamic. Though other types of local knowledge, such as “traditional,” “folk,” or “indigenous” knowledge, may take generations to develop, Maltz contends that certain types of local knowledge – like farmer knowledge – may develop even within one or two generations of place based experience. This suggests that research on local farmer knowledge of alternative agriculture may be possible even in places where a long tradition of agriculture is lacking. In this sense, soil and on-farm management of soil presents a unique entry point for studying farmer knowledge in alternative agriculture, particularly in the US – because regardless of the length of a farmer’s tenure, developing local knowledge of soil is foundational to farming alternatively. Local knowledge of soil enables knowledge holders to farm productively and understand the local ecological systems upon which their farm operation depends . At the same time, soil is heterogeneous across landscapes . For example, even at the scale of a single field, differences in soil microenvironments, management histories, inherent soil characteristics, and time of year can dramatically influence how a particular field can be most effectively managed. Addressing this challenge in soil management and understanding the nuances of soil management are fundamental to practicing alternative agriculture – where place-based knowledge of soil is an important aspect of building and sustaining healthy soils on-farm – and more broadly, resilient agriculture . In the U.S., there exists a handful of studies documenting rural local knowledge and rancher local knowledge . Very few studies explicitly examine local farmer knowledge in the context of alternative agriculture. To date, most formal studies on farmer knowledge tend to focus on farmer decision-making as it relates to the adoption of new practices . Even fewer studies currently exist at the intersection of farmer knowledge, alternative agriculture, and soil management. Though there is documentation of farmer knowledge of soil management in sustainable agriculture, most studies focus within the “development” context outside of US alternative agriculture . Similarly, research on indigenous knowledge of soil is frequently approached from an ethnopedological or traditional ecological knowledge perspective , and lacks focus on production agriculture. To consider this gap, we focus this exploratory study on a significant epicenter for alternative agriculture in the United States: present day Yolo County, California, also referred to as the unceded tribal lands of the Cachil Dehe Band of Wintun Indians of the Colusa Indian Community, the Kletsel Dehe Wintun Nation, and the Yocha Dehe Wintun Nation.