The new picture makes me think they may be too warm. Just to reiterate what Katie mentioned, it is often best to have the space large enough that the chicks can move away from the heat source.
~Anna
I think it is often pretty obvious. Although we had a thermometer, it was hard to read so not sure how much we really used it. If they are cold, they will huddle together under the light and if too hot...as far from the light as they can get. My chicks ended up sleeping under the light at...