Yeah, somehow unless you work in a feed store our little critters just aren't welcome at work. Go figger!
You are wise to consider that a heating pad you've had for awhile isn't a good idea, but that depends entirely on how old it is. Older pads, those just kinda stuck forgotten in the back of a bathroom cabinet, are not what I'd want anyone to use! The heating elements inside can become brittle and that's not good!
Walmart and Walgreen's do carry the pad that most of us use...it's the Sunbeam X-press heat and it says right on the box that it has a "stay on" feature - that's the most critical thing. You need a pad that doesn't shut itself off every two hours or so. For only 8 chicks you could certainly get by with the smaller sized pad as well.
As for the risks, as I tell anyone, anytime you are using an electrical device to produce heat, the risk is always the regardless of what you are using. My husband, who has been a electrician for over 40 years, would be the first to stop me if he thought I was taking unnecessary chances, believe me! (Even after being married to him for 49 years, I still got "the look and the lecture" when I grabbed the toaster cord and pulled it to unplug it rather than physically grasp the plug between thumb and forefinger and unplug the darn thing) But common sense goes a long way with any heating method. Make sure connections are secure. Make sure the pad is a relatively newer one. Make sure chicks can't trapped between the pad and the frame. Especially with your temperatures, there's no way the chicks need the pad on the highest setting anyway, so don't set it on high....start with 4 or 5 and watch the chicks' behavior. They'll tell you if they are comfortable. After the first few days you'll find they spend as much time sitting on top of it as they do under it, and if it was dangerously high they darn sure wouldn't be doing that. The heat is turned down gradually after the first critical couple of days, so it's just going to get cooler as their time as babies goes on. Test it before you use it...turn it on for a day and check it for any signs of being too warm or having problems. These aren't difficult precautions...they are basically the same thing you'd do with a heat lamp. Remember too that the heating pad doesn't heat the entire area the chicks are using, it just heats the chicks. And the heat needs to be near their backs, just as when they scoot under Mama Hen.
One of the biggest drawbacks to using a heating pad has been that when the power goes out, the pad goes off. Then it has to be turned back on and reset to "stay on". @Henless has found a pad that does all of the things we want a heating pad to do with the added advantage of turning itself back on after an outage and going to the last setting the pad was on....ingenious, and she really likes it! Here's a link to that pad:
http://www.sunbeam.com/pain-relief/...ology-blue/000771-810-000.html#sz=12&start=18
Now, as I said before, you sound like you have your entire setup geared toward using the reptile lamp, and if that's what you want to do that's great....there are thousands of people doing that and they are very happy. So I don't mean to sound like I am pushing anything off on you that is outside your comfort zone! I believe in MHP based on my own positive experiences with it, but I know it's not the only way to raise them and it's not always the best for each situation! I had mentioned it in my first post and am now just trying to answer your questions and concerns. If you just aren't comfortable, for goodness sake don't do it!