Overall, in the judgment bias test, the results indicated that the imprinted chicks were significantly more pessimistic than the control chicks when tested at the older age. The remaining results were non-significant. In the open field test and in the novel object test, there were no significant results. Lastly, the imprinted chicks weighed significantly less than the control chicks at all ages. The results were inconsistent with hypotheses (1), (2), and (3). The results indicated that imprinting on a model hen, did not have a positive impact on the emotional state of the chicks.
Some examples of potential limitations in this project, was that during the filial imprinting procedure, the sensitive period may have been missed and/or the chicks may not have imprinted on the model hen. I believe that the sensitive period was not missed, because the imprinting procedure was performed within 3 days. In future projects, experiments that confirm this should be included. The imprinted chicks may have felt unsafe without their model hen in the test arenas. In future projects, additional tests can be performed in the home pens (the imprinted chicks were provided with a model hen in their home pens), or the model hen can be included in the test arenas during experimentation.
Contrary to the study results of Higuchi, the imprinted chicks weighed significantly less than the control chicks. Possible explanations could be that the imprinted chicks were more stressed, or that they were more active in their home pens because they had access to the model hen as enrichment.
In conclusion, the results were inconsistent with all 3 hypotheses, indicating imprinting on a model hen, did not have a positive impact on the emotional state of the chicks. Further studies needs to be performed to find methods to reduce chick stress in layer hen commercial hatcheries, to improve their welfare.
