Miss. Code Ann. § 43-21-551: Miss. Code Ann. § 43-21-551

(1) Unless the hearing is continued upon a showing of good cause or the person who is a subject to the cause has admitted the allegations of the petition, an adjudicatory hearing shall be held within ninety (90) days after the filing of the petition to determine whether there is legally sufficient evidence to find that the child is a delinquent child, a child in need of supervision, a neglected child or an abused child. If the adjudicatory hearing is not held within the ninety (90) days, the petition shall be dismissed with prejudice.

(2) If the child is in detention, the hearing shall be held as soon as possible but not later than twenty-one (21) days after the child is first detained by the youth court unless the hearing be postponed:

(a) upon motion of the child;

(b) where process cannot be completed; or

(c) upon a judicial finding that a material witness is not presently available. If the adjudicatory hearing is not held or postponed for the aforesaid reasons, the child may be released from detention.

(3) If the child is held in shelter, the hearing shall be held as soon as possible but not later than thirty (30) days after the child is first taken into custody unless the hearing is postponed:

(a) upon motion of the child;

(b) where process cannot be completed; or

(c) upon a judicial finding that a material witness is not presently available. If the adjudicatory hearing is not held or postponed for the aforesaid reasons, the child may be released from shelter.