Domestic chicks, soon after hatching, move and interact with their environment to follow their mother hen, to join their mates and to find food. To navigate their environment, they use perceptual cues and landmarks. Nevertheless, they also learn more abstract rules. Let us imagine a chick that finds their food always under the third bush. It can remember specific features of such a bush. For example, its shape or its height; but they can also learn its ordinal position. To disentangle which information the chick is using in a completely natural environment may be hard, nevertheless in a laboratory setting, where we can better control their environment and for available cues, it is possible to specifically design a situation to understand if a chick can use ordinal information.

In a seminal experiment, day-old chicks learned to find their favorite food, a mealworm! in the fourth container in a series of 10 identical containers. Chicks learned to walk directly toward it in a few hours. They continued to directly go to the forth container also when the number of containers was reduced to five and the distance between them was increased. Day-old chicks did not use spatial information such as the exact position of the container in their environment, nor the distance from walls, or similar; but they used the ordinal cue. Likewise, they counted the containers to find their mealworm!

Related scientific publications:
Rugani, R., Regolin, L., & Vallortigara, G. (2007). Rudimental numerical competence in 5-day-old domestic chicks (Gallus gallus): Identification of ordinal position. Journal of Experimental Psychology: Animal Behavior Processes, 33(1), 21–31. https://doi.org/10.1037/0097-7403.33.1.21