I've ordered two batches, one was 25 chicks and one was 15. Of the 25, one chick died soon after arrival, but they had sent two extra. Of the 15, they all survived and thrived and there were 7 extra. Once they are eating and drinking in the brooder, I doubt you will have losses. Once they are in the run, they should all be good too, if you have built it well. In other words, I would bet that 95-100% of your chicks make it to laying age.