Despite the popular saying that “he who does not cry does not breastfeed”,asking for more does not always have the expected reward. According to a study by the Higher Council for Scientific Research (CSIC), lhatchlings that demand food more insistently grow less. The researchers, who have worked with chickens of the southern shrike, a bird widespread in the Iberian Peninsula, ensure that the offspring cannot manipulate the feeding patterns of their parents.
“The young of altricial birds, those that are born blind, without plumage and almost without mobility, ask for food through an extravagant and showy behavior. However, this behavior has a cost, sinceInsistent demands have a negative impact on the growth capacity and immune response of chickens“, explains the CSIC researcher Gregorio Moreno-Rueda, from the Arid Zones Experimental Station, who has published his conclusions in the journalJournal of Evolutionary Biology.
During the experiment, the research team separated two groups of chickens, which they subjected to the same environmental conditions and supplied the same amount of feed. However, one of the groups was encouraged tobeg for food for about 30 seconds per hour, while the other only asked for food two. After comparing the results, the researchers saw that the group of birds that requested food for less time had a higher growth rate and an immune response than the other group.
According to this study, for the signals to be honest and accurately reflect the chickens’ need, hunger in this case, they must be expensive to produce. Otherwise the chickens would ask their parents for more food than the parents are supposed to provide and a parent-child conflict would ensue.
“The results of our research could help usunderstand child psychology of humansas the crying of babies is analogous to the begging behavior of chickens. If our results can be extrapolated to child psychology,crying would be a waste of energy that would translate into a reduction in growth rate and immunocompetence“Moreno-Rueda comments.
