Knowing the penchant that chicks have for committing suicide, I completely enclosed my HP in fabric. Made the wire frame, set the HP on top, put the whole thing inside a pillow case, folding the case to wrap snugly around on all 4 sides, then used painter's tape to wrap completely around in multiple locations, being sure to bind any fabric overlaps securely so the little boogers couldn't worm their way in between the folds. Where the cord comes out, I slit the case, used electrical tape to secure the fitting between the pad and the cord, and then, just for good measure, ran a couple of courses of tape around the ragged edges of the hole.
I've been doing some thinking about my MHP set up for multiple ages. My older chicks don't need it now, but I just know that if I put the tinies in with a MHP, there will be some turf wars, and some tinies may get squished. So, I may just divide the brooder, giving the tinies room to come and go at will, but blocking the littles from the MHP side.
But, for those of you with multi-ages who still need the MHP, here's an idea: make it 2 level, with the bottom level built in the traditional fashion, but, put an excluder along the front that would allow the tinies in the lower level, but exclude the bigger chicks. Then, the upper level could have extra bedding at the sides, and the whole affair could be covered with a box to help retain heat at the upper level. You'd have to play around with heat settings, and put some extra ventilation holes in the box, just for safety, but it could double your brooding capacity. I think if I was going to do it this way, I'd build a frame, to be sure the MHP didn't shift and end up squishing some tinies.
