My chicks arrived in early April. If I remember correctly the temps were in the low to mid 60s during the day and 30s & 40s at night. They spent about 12 days in a shed (uninsulated, but sealed from drafts) that was heated with an oil-filled electric heater and had two heat lamps over their brooder. At two weeks we moved them to the screened porch with a draft guard around their brooder (a kid's pool) and their heat lamps. They did absolutely fine.
If I ever order chicks again I plan on brooding them the same way. Of course, I won't order winter chicks. In the springtime I think it works just fine to raise them outside, as long as you are able to keep the enclosure to the temp. necessary for their age.