I would expect between 2 and 6 weeks for them to start laying, unless they have major health issues that no-one yet knows about.
It takes a hen's body a certain amount of time (a few weeks) to make a supply of egg yolks ready to go, then she can produce one every day or so by adding the white & shell and laying it, while also keeping up the supply of properly-sized yolks.
I am assuming you are in the northern hemisphere, so the days are getting longer. If you are on the other side of the world, with days getting shorter, they may take a bit longer.