28 degrees in April is a stretch for most of the country, so I'd pump the brakes on blaming the lamp setup. Honest take, one 250 watt red bulb in a corner is exactly what tons of old timers ran with 25 to 30 chicks in a 4x4 box and it worked fine for decades. Your real problem sounds like the brooder was too big for the bulb size, and a second lamp just masks that by heating more air instead of giving them a proper warm zone to park under. Twelve chicks will pile up no matter what if the draft hits them, so I'd look at the box before I'd blame your uncle.

Man, my friend did the exact same thing on a dare from his cousin and ended up buying a 6 euro gelato out of pure defeat at the top of the hill. Just grab the metro card next time, it's like 7 euros for a day and your shirt stays dry.