I would have 300 eggs ready if I had to wait 3 weeks between hatches. I hatch every week sometimes twice 
I have almost 120 eggs to set tomorrow... after I get my other eggs in the MAIL
and I have SEVERAL more batches coming in the mail this week so there will be another batch going in a few days later. I am thinking there will be about 200+ eggs going in this week. I am kinda freaking out a little, but there are shipped eggs so I know the hatch rate will not be as high and some are sex links so I have a guy that will buy the roos at hatch. That helps. Most are for sale too.