Q) If a toddler is going to be three years on chol hamoed, can his parents do the chalakah before Pesach if needed, as there are visiting family?

A) There are different traditions in regards to the extent of time one should wait until the first hair cutting of a youngster. Some authors mention nine months (Heichal Avoidas Hashem 2,179), some two years (Peulas Hatzadik 3, 236). Orchois Rabeinu mentions that the Steipler Gaon ZT”L was lenient with his grand children after two years. Most common, however, is three years.(Maharam Brisk, Afraksta Deaniyo 161, et al.)

When in need, as for the comfort of the child) it could be done before the completion of full three years. When the three years finish during Sefirah or Chol Hamoed Pesach, one could preempt the Chalakah before Pesach. Nitey Gavriel, Tigalachas Hayelodim ch. 2 & 3)

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a