Draft:On-farm hatching

On-farm hatching is the process of hatching incubated eggs on the premises of a farm, as opposed to in a hatchery. On-farm hatched eggs are usually incubated at a hatchery before being transported to a farm a few days before they are due to hatch.

Hatching eggs on-farm means that chickens avoid exposure to hatchery conditions and live transport, and immediately gain access to the nutrition and enrichment available in a farmhouse. As commercial hatching may deprive chicks of food for the first 3 days of their lives and subject them to high levels of dust, pathogens and noise, on-farm hatching may provide several production and welfare benefits, including increased body weight, reduced footpad dermatitis,  reducing handling stress,  improved intestinal and immunological development,  and lower mortality.

While on-farm hatching has mostly been developed for use on broiler farms, in-ovo sexing of chicks may make on-farm hatching compatible with layer hen production.

History
In most layer hen and broiler production, chicks are hatched in a hatchery. After incubating for 18 days, the eggs are transferred to a hatching basket that is climatically regulated to ensure optimal conditions for hatching. The chicks then hatch in a 24 to 48 hour window, before they are processed and transported to the farms on which they will be raised. During this process, chicks can be exposed to "high levels of dust, pathogens and noise and often continuous darkness," and may go up to 3 days without receiving food and water before they reach the farm.

On-farm hatching emerged in Europe as an alternative process for hatching chicks that may offer production and animal welfare benefits. It has been in development at least since 2004.

Advantages
In broiler production, a key outcome of interest for farmers is the weight of chickens at slaughter. In the academic literature, findings on the effect of on-farm hatching on the weight of animals mostly show positive results, although with some variation. Two studies comparing the outcomes of chickens hatched using Vencomatic’s X-Treck system to chickens hatched in a conventional hatchery with and without nutritional supplement found that on-farm hatched chickens were heavier than traditionally hatched chickens from the time of hatching up to near slaughter age. The increased body weight on on-farm hatched chickens may be one reason that on-farm hatched chickens move less in barns than traditionally hatched chickens. Another study, however, found that on-farm hatched chickens were heavier up to 21 days after hatching, but that weight differences relative to chickens hatched in conventional hatcheries were statistically insignificant thereafter.

On-farm hatching can also affect other production-relevant outcomes. For instance, a Belgian study deploying an experiment to analyze the outcomes of chickens hatched on-farm relative to in hatcheries found that on-farm hatching resulted in higher egg hatching rates and lower chicken mortality. The finding on lower total mortality is supported by a quantitative meta-analysis showing that post-hatch food and water deprivation ― as may occur when hatching is conducted in a commercial hatchery ― is associated with significantly higher total flock mortality across 29 studies.

The improvements to animal health can also reduce farmer costs on animal health interventions as well as the quantity of antibiotics used in poultry production. In a study of Belgian broiler chicken producers, farms using on-farm hatching methods were found to use 5.6 times less antibiotics than farms receiving already-hatched chickens. Among those that did use antibiotics, farms implementing on-farm hatching also used less antibiotics, especially during the early days of the chickens' lives.

On-farm hatching may also boost the performance of layer hens. Although the effects of on-farm hatching on layer hen production is less well studied, one analysis found that commercially hatched chicks "laid fewer and smaller eggs than chicks hatched and handled under calm circumstances."

Disadvantages
Despite the potential benefits to broiler and egg production, on-farm hatching may also impose additional production costs. Some on-farm hatching solutions require substantial additional investments in infrastructure and equipment to operate. On-farm hatching also requires the installation and operation of climate control systems on farms to achieve optimal conditions for hatching chicks. Finally, once the eggs have hatched on-farm, unhatched eggs also have to be collected, and unviable chicks must be identified and euthanized, requiring extra farm labor.

Advantages
Many of the potential animal welfare benefits of on-farm hatching derive from chicks avoiding exposure to the adverse conditions and deprivation of nourishment they may experience when hatched in a hatchery. In conventional hatching, chicks may be left in the incubator for 24 to 48 hours while incubator operators wait for most of the eggs to have hatched. From there, the chicks undergo processing and are transported onward to their designated farms. Unless special provisions are made, this process means that chicks do not have access to food and water for up to 72 hours after hatching.

The lack of food and water in the early days of chicks' lives is associated with several detrimental effects on their wellbeing. A meta-analysis of the effects of early feeding on the outcomes of broiler chickens found that post-hatch food and water deprivation was associated with lower body weights up to six weeks of age and higher total mortality after seven weeks (which is about the slaughter age of commercial broiler chickens). A controlled experiment on the effects of on-farm hatching also found that on-farm hatching results in lower total mortality.

With regards to the physiological welfare of chickens, one study found that on-farm hatching was significantly associated with lower footpad dermatitis compared to traditionally hatched broiler chickens. The authors speculate that this may be due to reduced litter moisture also observed in another study of on-farm hatching, which also found reduced footpad dermatitis. Post-hatch food and water deprivation has also been shown to cause adverse effects on immunological and gastrointestinal systems of chicks. At the same time, the type of hatching system was not found to have a distinguishable effect on plumage cleanliness, skin lesions, hock burn, or the gait quality of chickens.

Conventional hatchery environments are also associated with several negative implications for animal welfare. Hatcheries are prone to developing high levels of dust and pathogenic material, and the operation of machinery and chirping of hatched chicks can make them very noisy environments. These factors may contribute to the elevated mortality observed in conventionally hatched chicks relative to on-farm hatched chicks. They may also adversely affect the psychological welfare of chicks. For instance, a study from Linkoping University found that chickens hatched in a conventional hatchery had higher corticosterone levels ― a hormone produced during chickens' stress response ― than a set of control chicks immediately after hatching and after transport to the farm. Chicks hatched in a hatchery also displayed an elevated stress response when subjected to a restraint test 6 and 41 days after hatching. Similarly, layer chicks hatched on-farm had lower corticosterone levels after transport than those first hatched in a hatchery and then transported to the farm.

Overall, the European Food Safety Administration recommends on-farm hatching due to its reduction or elimination of the handling stress, resting problems, prolonged thirst, and prolonged hunger experienced by newly-hatched chicks in conventional hatcheries.

Disadvantages
In terms of disadvantages, one study found that layer hens hatched on-farm had more severe keel bone fractures than those hatched in a conventional hatchery. The authors postulate that the difference is caused by different behaviors adopted by on-farm hatched chickens, although note that more research is required to fully understand the cause. The same study also found that on-farm hatched chicks display less movement on farms than conventionally hatched chicks, and postulated that the early life stresses of hatcheries may better prepare conventionally hatched chicks for the stresses they may experience on farm.

Home Hatching
Home Hatching is an on-farm hatching system in which setter trays with incubated eggs are placed on racks held up by a system of rails. Once the eggs hatch, the chicks drop onto a littered barn floor where they can access feed and water. To maintain optimal conditions for hatching and the early days of the chicks' lives, infrared heaters are installed below the racks.

An early version of the Home Hatching system was meant to be attached to a system of winches that could raise the rails once hatching was complete. However, the system has since been updated to allow the rails to fold together such that it can be easily be removed from the barn without needing to install a suspension system.

NestBorn
NestBorn is an on-farm hatching system that places incubated eggs directly onto litter beds that have been prepared on the floor of a barn. Eggs are typically placed on the litter bed by a specialized NestBorn machine, but the solution otherwise requires few new investments. Before the arrival of eggs, the farm house must be cleaned, disinfected and dried to protect the chickens from infections, and the house should be preheated to a maximum of 28$^{\circ}$C. NestBorn have also developed a barn monitoring device and platform that measures the climatic conditions of the barns so they can be optimized for hatching.

One2Born
One2Born offers an on-farm hatching solution that requires minimal investment into new equipment. In One2Born, eggs at 18 days of incubation are placed on "hatchholders" that are transported to the barn in which they will hatch. The hatchholders resemble conventional egg trays with some design features to allow for improved air flow, and are placed directly onto the littered floor of a pre-heated barn. Once the eggs hatch, the chicks can easily descend onto the barn floor, and the hatchholders, which are biodegradable, can be collected for recycling or composting, or be left for use as an environmental enrichment for the chickens to interact with or rest on.

Patio
Patio is a whole-barn installation designed by Vencomatic for on-farm hatching. The basic unit of the system is a "cell", which is composed of two rows of six vertically stacked "tiers" on which hatched chickens spend their entire lives. At the top of each tier, a transport system carries setter trays with incubated eggs into the tier, and, below this, a conveyor belt system delivers water, feed and litter to the birds. Once a bird hatches from its egg, it falls down from its setter tray to the conveyor belt, providing it with immediate access to food and water. Patio cells can be placed adjacent to one another to fill out an entire barn.

Barns using the Patio system also require extensive climate controls. Implementing Patio therefore often requires extensive investments and equipment upgrades, but automates a significant amount of the broiler production process.

X-Treck
X-Treck is another Vencomatic on-farm hatching solution designed to allow for on-farm hatching in traditional broiler houses. The system is composed of elevated rails on which setter trays filled with eggs are placed. The rails are suspended in the air to allow for robust air circulation. When the eggs are about to hatch, the system is lowered toward the floor so that hatched chicks drop only need to drop a short distance to food and water at the floor level. Placing setter trays on the rails can either be done manually or by an automated system developed by Vencomatic. Climate and environmental conditions for the eggs can be controlled by a mixture of barnhouse climate controls and the elevation level of the X-Treck rails.

Adoption
On-farm hatching has mainly been adopted in Europe, the continent on which it was developed. Innovate Animal Ag, a thinktank that publishes research on emerging technologies in animal agriculture, estimates over 500 million broilers are hatched in Europe (primarily using NestBorn and Vencomatic solutions), comprising at least 8% of the market.

Some companies, such as the Belgian retail conglomerate Colruyt Group, have mandated the use of on-farm hatching across its supply chain due to its animal welfare benefits. Crown Farms, a subsidiary of UK food producer Cranswick that focused on chicken production, have also adopted on-farm hatching across its entire supply chain and report improvements in weight gains and the uniformity of the reared chicken. In the US, Perdue Farms is exploring how to incorporate on-farm hatching into their operations due to its potential to improve chick quality and welfare.

On-farm hatching is mostly used in broiler production, but can also be used for layers when combined with in-ovo sexing, which allows for the separation of female and male chicks before the eggs hatch on the farm.