Inspired by a poster a few days ago, I decided to modify my MHP In a way that was a bit easier to adjust that just the hardwire. I have a lot of chicks right now (50 + 42 more coming next week) but I use the smaller pads since I like the slide control and not having to worry about turning off auto off or having it not come back on by itself. Plus, I get more square footage for the money. So, yesterday I bought another pad ($13) and three cookie cooling racks (10x16) for $3.50 each.
At home depot I got some small bungies for $2.50. I went to TSC for the leg hardware since you pay by the pound. I got short (2.5"), medium (3.5") and long (5") bolts for each (that is, 6 bolts of each size since I have three pads) as well as 8 nuts and 8 washers for each pad, which came to a little over $6.
I got three different sizes because 1) they were only partially threaded and 2) I raise guineas, bantams, and standards so I need a bit of height flexibility to accommodate the different size babies.
I put the pad on the side without the rack's built in feet because they interfere with it laying flat since the rack is 10" wide but the pad needs to hang over an inch on each side. I used three bungies on each though two would hold it fine.
Here is one of the racks with legs installed and the order of the hardware.
I have about .5 to 1" of height adjustability with each size bolt. Again, fully threaded bolts would be better but this was cheaper. I used 3/8" hardware to save on weight and cost but you can certainly fit 7/16 or probably 1/2"