Find your local egg sellers, I've had the best luck with the "side of the road" vendors since they typically have roosters and don't refrigerate their eggs. You're probably going to get mutts of some sort but they will more than likely hatch a chick and are the same price as eating eggs. I have a group that I buy duck, turkey, and chicken eggs from and they will set aside specific eggs during the week so I can pick them up the next Saturday, but I've purchased 100's of eggs from them. Payment in advance with a smile never hurts either.
However, my question for you: are you prepared to hatch 150 (75% hatch) chicks in one shot? Without a dedicated hatcher, multiple brooders, lots of feeders, waters, heat lamps, etc., you're going to have a huge mess on your hands in 21 days. You also have to be prepared when those chicks get bigger and need more space. Then what happens if they don't sell? 150 chicks take up a lot of room at one week and it is quite literally exponential after that. Feed is going to get more expensive every day, maintenance time will go up, they'll need even MORE room...... I hope you have a plan.
Coming from someone who tried to cram a 270 egg hatcher full of eggs: take it slow. Do staggered hatches of 25 a week and test the market. If they're not selling, stop adding. If they're selling like crazy, add as many every week as you can. If something like the holiday season slows down sales, you can adjust as necessary. Hatching out 20-25 chicks a week is very manageable if you're paying attention and is very rewarding when they are selling. Once you get the hang of it, do 25-50 a week, then 50-100, maybe you'll need a bigger incubator after that...
Without your processes firmly in place to accommodate 100+ chicks from day one to three months, it's going to be a rough and expensive ride. Been there, done that, even have some chicks (still) that never sold.
Good luck!
