I have cats and dogs so I wanted my chicks to be safe but I also wanted the opportunity to expose the cats and dogs to them in a controled way so that as the chicks grew my other animals would know they were mine.
Everybody started out in the box, as the chicks grew (and more hatched) we did have to expand to a 2nd box but they were both set up identically.
The bulb is just a 40 watt bulb like I used in the styrofoam incubator. As you can see they are too warm, so I switched to a 25 watt and they liked that much better.
The naughty chicks were kicking all their shavings into their food and water dishes so I put a piece of a 2X4 under the dishes. It was short enough for them to hop up but tall enough to keep the shavings out. Although it is not in this photo I did have a quart size Mason Jar style waterer for them.
I would allow the cats and dogs in to view the chicks one at a time, I would take out a chick and let them smell it and see what all the chirping was. My Chesapeak is so bored with the chickens she wouldn't even acknowledge one in her kennel when it was AWOL. I also have a Blonde Lab, she is still excited about the chickens but she did find my AWOL chicken for me (more than once now) and both times she merely marked where the bird was under the brush and weeds but did NOT go after the bird. And as for the cats, well...
These cats are very protective of my birds but do chase and kill wild birds. I have watched them kill countless small birds and rodents that have gotten in and around the coop and run. They have also teamed up to chase off larger predatory birds. The one time we had a close call with a magpie that was going after some of my young pullets the white cat, Misty, threw such a hissy fit in the house that she alerted me to the squawking. I yanked open the door to run out and she ran between my feet and leaped the fence to bat the magpie and send it tumbling. It flew away but I was really impressed!