Hi there,
Those homemade cages are great as a temporary home. We use them for the first 2-3 weeks. It allows us to monitor how much they are eating as a small group, and also lets us begin sorting them out by size. We can also use them to do a quick head count, as it is hard to count 20 or so babies in a single cage.
However, since you are dealing with a single chameleon, you should consider purchasing something more sturdy. For a 1 month old chameleon I would purchase a 22 gallon reptarium or a small all-aluminum screen cage.
You will still need to purchase an acceptable bulb. For a small cage, use a combination of an 18" Zoomed Reptisun and a 40-60 watt heat bulb. I would advise against keeping your baby near an open window. A small enclosure and a small chameleon can overheat very quickly if left in direct sunlight.
Good Luck!

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Farrah & Vincent
Email: Screameleons@yahoo.com
Phone: (571) 437-0642
Website: http://www.Screameleons.com