The hens also changed their behaviour, and reacted with increased alertness, decreased preening and increased vocalisations directed to their chicks.
母鸡也会改变行为，提高警觉性，减少梳理羽毛的次数，增加向雏鸡发声的次数。
2
Studies have noted that vocalisations that some apes make while being tickled are similar to those made when they are playing, and acoustically they share some characteristics with human laughter.