In all honesty, this item has both good and bad points to consider. It's pretty much a trade-off! I purchased the smallest size tray because my flock is small, only 8 baby chicks. They spent their first 3 weeks in a cage inside my house, not in a coop so they were in a climate controlled environment. At first this tray was the perfect size. They all fit comfortably underneath it and it worked well. Within a week, they had grown enough, some could only fit parts of their body under the tray. The heating part always felt rather hot to me and I was constantly raising and adjusting the legs. By the 3rd week, the chicks wouldn't sleep under it at all and we moved them to the coop. It was a big adjustment. The nights here are still chilly and every time I checked on them, they were all jostling to get under the tray. Some were shaking from the cold and the tray just wasn't big enough to accomodate them all. Currently we're using the old heat lamp and that does the trick. They all have the warmth they need. If you're determined to buy this heating tray, I would suggest buying the biggest size you can afford. Chicks are guaranteed to grow! Expect to raise the adjustment on the legs quite frequently to fit the needs and temperature of your situation. The tee-pee top is a must if you want to save yourself extra work. Otherwise the chicks sit and poop all over the top and it's a hot mess! Looking back, the tray made the first week a breeze but after that, it's value diminished. For a large flock of baby chicks, I wouldn't recommend this tray at all. A pecking order is established early among every flock, even wth young chicks and the lower ranking chicks are pushed out beneath the tray while dominant chicks enjoy the heat. Once a chick gets chilled, there's a good chance it could become sickly and die. We were lucky to have a back-up, a heat lamp, otherwise I don't think all of my small flock would've made it. Sometimes you just can't build a better mousetrap!
