brooder help

[John01]

I am getting 5 chicks next week. I originally built a nice 4' x 4' wooden box for them. I was going to put it in an unheated shed outside my home with a 250 watt heat lamp. Well I set it up today and cannot get the temperature up where it needs to be.
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So i'm scapping that plan and I'm just gonna get a plastic tub at Wal-mart & keep them in the basement. Question is how big of a tub do I need for 5 chicks & how long can they stay in it before upsizing?

Thanks for your help

 

[tororider]

Have you tried putting something like cardboard or sheet isocyanurate along the walls of the 4x4 box to see if that helps keep the heat in before you scrap your I assume builtifully build brooder?