Earlier, DH went into the shed to check on them and found one of them perched on the rim of the brooder wall. That signalled that we had to make some changes. If a chick flew out of the brooder, it might not be able to fly back in, it would get chilled, and that would be the end of it.
We discussed putting something over the top. We discussed moving the brooder ring out completely. It's a bit early to do that really, we would normally do that next week, once the chicks are bigger and need more space.
In the end, we decided to move the ring out completely. This has the added advantage that it gives the chicks more space away from the heat lamp, so a bit more choice about how warm they want to be.
I tool a quick snap from the spycam. You can'tget any sense of the size of the area, but the chooks look perfectly content.