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تقول العرب: أَفْرَخَتِ الْبَيْضَةُ إذا خرج فرخها، كما يقال مجازا للرجل: أُفْرِخْ رَوْعَكَ، أي سَكِّنْ جَأشَكَ، ومعناه: ليخرج عنك فَزَعُك كما يخرج الفرخ عن البيضة.

The Arabs say:  the egg is hatched if its chick comes out, and it is said equally to someone to  “hatch his fear”  to mean “ calm down his fright”, which means by extrapolation: “let your fright out of yourself like a chick that is hatched out of an egg”.