Hatchability in broiler eggs varied widely depending on both the temperature used during incubation and the substance injected into the egg, according to the study. The highest reported hatchability was 89.86% among eggs given glucose and incubated at 37.5°C. The lowest was 48.33% among eggs given vitamin D3 and incubated at 36.5°C.
The findings point to an interaction between the two parts of the setup: the apparent effect of an in-ovo treatment differed according to incubation temperature. That was the central question of the experiment, which examined eggshell temperature, embryonic survival, hatchability, chick quality and later growth performance in broiler chickens.
What the experiment tested
The researchers used 1,200 fertile eggs from a 58-week-old Arbor Acres breeder flock. The eggs were reported to weigh 62 ± 1 grams. Four hundred eggs were assigned to each of three programmed incubation temperatures: 36.5°C, 37.0°C and 37.5°C.
The experiment used a three-by-three factorial design, meaning that each of the three temperatures was paired with each of three egg-treatment groups. After candling on embryonic day 10, eggs were randomly assigned to a handled, perforated control group, a glucose group or a vitamin D3 group. There were four independent replicates in each temperature-by-treatment combination, and the replicate, rather than each individual egg, was the unit used for analysis.
On day 10, each treated egg received 0.2 millilitres through the air sac. The glucose solution contained 5 milligrams per millilitre, while the vitamin D3 solution contained 25 milligrams per millilitre. The controls were perforated and handled but not injected.
The researchers analysed the results with a two-way analysis of variance, a statistical test used here to examine the effects of incubation temperature, in-ovo feeding and their combination. The reported differences were assessed against the study's threshold of a probability value below 0.05.
Temperature changed the pattern
Before the eggs were treated, eggshell temperature rose as the programmed incubation temperature increased from 36.5°C to 37.0°C and 37.5°C during embryonic days 1 to 9. The reported difference met the study's statistical threshold.
After the injections, treatment-related differences in eggshell temperature appeared on embryonic days 12, 14, 17, 18, 19 and 20. The temperature-by-treatment interaction means that the treatment differences varied with incubation temperature.
The hatchability result followed the same broad pattern of temperature-dependent differences. Among the feeding treatments, the glucose group had lower embryonic mortality than the vitamin D3 and control groups. The study also reported that incubation temperature and treatment affected external pipping and hatching times. Eggs incubated at 37.5°C were generally earliest, while glucose-treated eggs were earlier than controls.
What the result can and cannot say
The result is specific to the combinations tested in this experiment: the eggs came from a 58-week-old Arbor Acres breeder flock, and the researchers tested one concentration each of glucose and vitamin D3. It does not identify an optimal dose or establish that one of the lower temperatures is preferable for commercial incubation.
The reported hatchability percentages compare the tested temperature-by-treatment cells, but the supplied analysis does not include full cell-level estimates or confidence intervals. The experiment used four independent replicates per cell, so eggs within a replicate were not treated as separate independent observations.
The animal procedures were approved by the Shandong Agricultural University Animal Care and Use Committee and followed national guidelines for experimental animals. Further work would be needed to determine whether the pattern holds with other doses, flocks or production-scale hatchery conditions.
Paper data and sources
Original title: Effects of incubation temperature and in ovo supplementation of glucose and vitamin D3 on eggshell temperature, embryonic mortality, hatchability, chick quality, and post-hatch performance in broiler chickens
Authors: Okai M, Kruenti F, Nadiedjoa Y et al.
Journal/Repository: Frontiers in physiology
Status: Peer-reviewed
First online: 2026-10-08
DOI: Not available
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