No. Often you will see rocking around the 17th day. This is because the chicks are turning toward the big end of the egg. Usually after this initial rocking they will go quiet until they start getting ready for actual hatch. I do not recommend early lockdown unless you hear chirping from within the egg, which signifies an internal pip or you have early external pips, in which case you should check temps and the accuracy of the thermometers as high average temps can early hatches.