I don't think the issue will be when the chicks are tiny, assuming you're able to maintain a warm temp in the storage tote/brooder. I guess I see more issues with what accomodations will you be making for them when they outgrow the tote (which would be pretty quickly), but aren't fully feathered enough to withstand our winter temps?? Do you have a larger area for them when they're 4, 5, 6, and 7 weeks old (because some are slow to mature/feather out) where they can still take advantage of heat?? Because they will outgrow one of those plastic storage bins pretty quickly... I'd opt to wait till spring, but I know that's easier said than done sometimes...