I don’t believe in any magic numbers for chick or chicken space. There are just too many variables. I do think that is small, not because or square feet per chick but because you don’t have a lot of room in there for food, water, that Eco Glow, and for them to play. If that is in the house it isn’t too bad because you have steady temperatures to deal with, but to me the best brooder is one that keeps one area warm enough in the coolest temperatures and cool enough in the warmest temperatures, however you provide that heat.
That can be harder to do when you are brooding outside. I am in lockdown now and in a few days will be putting chicks in my brooder built into the coop. According to forecasts they will have overnight lows below freezing and a little later will have daytime highs well into the 60’s. I get around that by using heat lamps (securely wired in place because I am concerned about fire potential) to keep one area warm enough when it’s below freezing but my 3’ x 6’ brooder is big enough and well-enough ventilated that the far reaches will be cool enough even in the warmer weather.
I have never used an Eco Glow so I have no idea how cold it will work, but Junebuggena usually knows what she is talking about. I’d trust her.
How soon they can go out depends on a few things. If they are exposed to cold they feather out faster. They acclimate also. I was once living outside Cadiz Spain in 90F (32C) weather and flew to Edinburgh Scotland where it was right at freezing with a snowy slush mess falling and the wind blowing. I was dressed appropriately but still froze. Acclimating is more than just feathering out. Lots of people that brood in the house or another building that is fairly warm take the chicks outside for a while in cold weather. They are usually surprised at how well the chicks handle that. But just a short while in cold temperatures really helps.
How you feed them has an effect in how fast they feather out. A chick Starter at 20% protein will help them feather out faster than a 16% Grower, for example.
The facility they are moving into has an effect. It needs ventilation but you do not want a breeze blowing onto them. My grow-out coop has a top that is mostly hardware cloth with a raised roof to keep rain out. Great ventilation. But the area down where they are is extremely well protected against any wind. Chicks from my brooder have gone through nights in the mid 20’s F (-4C) in this unheated coop before they were 6 weeks old.
I don’t know what temperatures you might see in Ontario in May. I don’t know how you are going to raise them. But especially if you expose them to cooler temperatures seven weeks sound long enough to keep them inside.
Good luck!
