If performing a float test, it’s always very important to check for any external peeps, like you mentioned, failure to detect a peep can be fatal. It also has to be done fast, to prevent from temperature shock. As far as candling vs float, I have done both. Although candling let’s you SEE inside the egg, at day 21 and beyond, it gets very difficult to see anything g besides a black shadow and the air pocket. Many times , chicks won’t move or even make noise to give us a sign of life. Floating the eggs PROPERLY, can help determine weather the chick is still alive or if the egg was even fertile in the first place. Maybe the best thing to do is a combination of both candling & float

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Regardless, thank you for your input, I’ll be sure to apply it.