I want to see the answer to this too. Of the 17 chicks we got from Murray McMurray, 15 died in 13 days. Yet, the other two, a Rhode Island Red and a Pearl White Leghorn, are thriving.
My guineas were pecking at the nipple waterer so much, that they were soaking the brooder box. Personally, I have come to the conclusion, that I might have had too many chicks in one brooder. 17, in a 2'x3' brooder. I even moved them to a second identical brooder, with the same result. Yet, the guineas, and turkeys, thrived. For those two weeks, every day, I'd find a dead one at the bottom of the pileup, under the heat lamp. I never figured it out. All 17, were vaccinated for the two diseases that were recommended. Yet, the "Meat and Egg combo" package all died, and the two breed specific birds, are doing well. Hmmmm. I don't know. But, as for your guineas, I don't know what to tell you. Let's see what folks more knowledgeable than me, have to say. But, mine, LOVE the nipple waterer. They are outside maybe 40' from me, and I can hear the tapping at the nipples, as I type this.