Carbon accounting for layer hen operation has remained underdeveloped at the township scale in North China. There is an ever-increasing need for precise mitigation planning for the high production intensity. In this study, the whole-chain carbon emissions were quantified to identify the spatial hotspots for the mitigation potential of coordinated low-carbon technologies in a typical layer-hen-intensive township in Quzhou County, Hebei Province, China, during 2023–2025. A hybrid life cycle was assessed to combine with the Intergovernmental Panel on Climate Change greenhouse gas accounting framework. The boundary also covered feed crop production, feed processing and transport, layer rearing, manure removal and storage, as well as manure treatment with resource utilization. Carbon emissions were estimated, according to three consecutive years of field survey data from more than 300-layer-hen households, together with parameters from livestock studies and emission factors from the Ecoinvent version 3.9 database. Annual emissions were calculated per kilogram of eggs and per bird. Three scenarios were selected, including the baseline, multiple single-factor optimization, and an integrated optimization. A series of experiments was conducted to evaluate the independent and combined mitigation of breed improvement, feed reformulation, housing upgrades, manure treatment, and composting optimization. The results showed that there was an outstanding transition towards intensified production. The number of farming entities decreased from 382 to 310, whereas the standing population increased from 5.80 to 6.90 million, indicating a shift towards fewer but larger operations. The total annual carbon emissions declined from 42600 to 31200 t of carbon dioxide equivalent, rather than herd expansion, with a cumulative decrease of 26.8%. Carbon intensity per kilogram of eggs decreased from 0.92 to 0.78 kilograms of carbon dioxide equivalent, while annual emissions per bird decreased from 25.3 to 23.5 kg of carbon dioxide equivalent. The production efficiency was more than offset by the upward pressure from inventory growth. Spatial patterns also changed at the village scale. In 2023, high-emission villages were concentrated in the central and western parts of the township, with the villages emitting over 7000 t annually. In 2024, the hotspot area contracted markedly, and by 2025, most villages shifted to lower emission levels, below 4000 t per year. There was a transition from clustered high-emission hotspots to a more evenly distributed low-emission structure. Emission-source analysis showed that the feed process and manure treatment dominated the carbon footprint. Feed production and processing contributed about 30% of total emissions, manure removal and storage accounted for about 25%, and feed cultivation contributed about 24%, whereas transport contributed less than 2%. Feed processing and manure treatment declined by 38% over the study period, indicating the largest total reduction. Decomposition analysis indicated that the high efficiency was the leading driver of emission reduction, followed by structure optimization with scaling-up and intensification, while herd expansion remained the main factor increasing emissions. Scenario analysis further revealed that there was considerable but uneven mitigation. Post-farm manure delivered the greatest standalone reduction potential, with cumulative independent contributions of 40%. On-farm measures contributed 17%, and pre-farm interventions, especially feed optimization, contributed 16%. All optimal measures were combined in the production chain. The maximum integrated mitigation potential reached 52%, avoiding the overestimation from directly summing single-factor effects. Overall, the carbon accounting at the township scale can be expected to effectively capture structural and spatial dynamics of carbon emissions in layer hen production. The most effective pathway can be identified to coordinate the feed systems, production efficiency, and manure treatment. The finding can also provide a strong reference to reduce carbon emissions for the low-carbon transition of the layer hen industry in North China.

North China has been one of the main regions in laying hens breeding. There is a high demand to standardize the carbon emission accounting of the laying hen breeding industry at present, in order to formulate carbon emission reduction technologies and policies in the carbon emission inventory of the animal husbandry industry. Particularly, carbon emissions are ever-increasing, as the laying hen industry is developing rapidly. However, it is still lacking in the carbon emissions of the whole industry chain in the layer breeding. This study aims to improve the carbon emission factors of the layer breeding industry in North China. A carbon emission accounting was also implemented for the layer breeding industry, according to the IPCC national greenhouse gas inventory guidelines. The mixed life cycle was then adopted to assess. The data was collected from the field research and meta-analysis data. 362-layer farms in Hebei Province were taken as an example. The benefits of carbon emission reduction were calculated from the whole chain (feed planting and processing, layer feeding, and manure management). Furthermore, the carbon emission sources were determined for the whole industry chain in the layer breeding. The results showed that the annual carbon emissions (in terms of carbon dioxide equivalent) per layer in the small, medium and large-scale farms were 25.6, 24.4 and 23.0 kg, respectively. The main emission sources were feed production (56.0%), enteric fermentation of laying hens (9.0%), egg packaging (9.0%), and manure storage and treatment (5.0%). The precise feeding was obtained to improve the manure cleaning. The optimal manure treatment also reduced the carbon emissions. There were also the traditional modes of laying hen breeding and extensive management. For example, the amount of feed varied by 5% to 10% among different farmers. A comparison was performed on the farms with the different size scales. Some measures were taken to avoid wasting resources. The large amount of carbon emission was needed to improve during the laying hen breeding. According to the survey, a series of measures were proposed to reduce carbon emissions, including specific ingredients in the feed, optimal feed structure, and better waste disposal. The laying hen breeding industry should be transformed in the direction of modernization, scale, standardization and automation. The precise feeding can be expected to improve feed utilization and energy saving. The level of waste treatment can also be promoted to reduce greenhouse gas emissions for the green and coordinated development of the laying hen industry. The carbon emission also accounted for the carbon emissions in the whole life cycle of layer breeding. The finding can provide a strong reference to analyze the carbon emission of layer breeding in different scale farms and emission sources. Carbon emission reduction measures are also suitable for different farms. Data support can also be offered to assess the carbon emissions intensity of the layer breeding industry.