Ibne Umar (radiyAllahu anhuma) narrates that Rasulullāh ﷺ once saw a boy whose head was shaven partly, he forbade this and said: “Either shave it all or leave it all.”
1. To shorten or shave part of the head and to leave remaining hair long is prohibited in the hadith.
2. The prohibition is for both adults and kids.
SOURCE: ORCHARD OF KNOWLEDGE