Three weeks in, just when we thought we'd gotten the hang of adjusting temperatures, accepting the fact that chicks will scatter ⅔ of their food while eating the remainder and patiently clearing and re-clearing their water dish of the shavings they constantly scratch into it, one of the chicks died. They were all fine one morning, and 3 hours later, one was dead for no apparent reason. We later learned that this 'sudden death' thing isn't uncommon with chicks and thankfully, we haven't repeated the experience.
But by the time I moved the chicks outside, I had some serious doubts regarding whether they were all pullets or not. As time went on, it became more and more clear that Flutter and Popcorn were definitely NOT hens. Popcorn even croaked/crowed at me once when I went in to let the chickens out for the day one morning. And Burnside was becoming a more expensive hen all the while because the city rules are that, roosters are not allowed in our zone. This means we will have to either eat them or sell them for someone else to eat, and our hen was a '1 for the price of 4' deal.