Schlecht Hatchery is hands down the best I've used and I've used dozens of hatcheries for broilers. All hatcheries are gong to vary from batch to batch... that's the nature of the business as the quality of the chicks has more to do with the breeders themselves. However the incubators have a huge say in how the chicks hatch and thrive. For instance if the temp fluctuates too much, say it gets too hot... the chicks will hatch a few hours early and will not thrive. They will be smaller when you get them and you are less likely to have problems. Only once have I had this happen with Schlecht but all were replaced the next week. They are a small hatchery and the owner actually has a catering business too so I'm assuming the incubators are not state of the art and fluctuations do happen. However the service and price outweigh any other issues that I have dealt with. Hands down a class act.
However there are other hatcheries that have amazing incubator systems that keep this from happening, but the price also reflects this. Welp, Moyers, and Meyers have state of the art facilities but the price for all have went up in the last few years drastically. Probably to help pay for the millions that are invested.
I've heard mixed reviews from central.... so I'm not sure. I have never ordered from them, just chatted on the phone a couple of times.