please critique my heating pad technique!

So my 4 buff orpington chicks will be coming home in a couple weeks and I'm testing out the brooder trying the heating pad technique. Ive used hardware cloth but doubled up the sides by cutting a piece larger than the heating pad and folding edges over in order to make the frame firm. I shaped it so that there is an exit on 2 ends, and i shaped it lower on one side than the other so the chicks can grow in it a bit. Given that im only getting 4 chicks i didnt see space as a huge issue. The lower end registers at almost 90 and that is approx an inch from the surface of the pad, so if chicks wanted to nuzzle their backs right up to it it will easily be over 90. The higher end is obviously cooler. I let the pad extend down on the short end of the frame for extra heat on that side.
I used electrical tape to really secure edges of frame and carefully pad any cut edges. I dont think i plan to secure the pad down to the frame (or should i?), if i do i may use large binder clips. I also plan to lie a peice of puppy pad on top to keep from getting the pad messy with poop and pee. That too could be clipped to the frame as well. As far as you can see, is there room for improvement here? Im a first time chicken mommy.

It's best to have a flexible frame which will be very close and touching the chicks' backs during the first week when their heat needs are highest. By week two, the frame may be shaped so it doesn't rest on the chicks' backs, thus reducing the heat effect by a small amount. Also, if the ambient temps are mild, you may be lowering the setting on the pad. By week three, the frame should be taller since the heat needs of the chicks are decreasing by quite a bit by now. Also the chicks will be four times larger than they were as day-olds. Will they still fit under the frame you've designed?

By week four, the chicks may be spending more time on top of it than under it. The frame needs to be sturdy enough it won't collapse under the weight of the chicks who will be eight times as big by now as they were at the beginning of the first week.

If you want further advice, you need to show how you plan to attach the pad to your frame. That's an area where there could be costly mistakes if you fail to get it right in that chicks might get trapped between the pad and the frame.

I havent worked out how to attach except wondering if many binder clips would work. As for touching the backs of the chicks...one side already will. There will onlu be 4 chicks. Should the whole 12x15 pad touch the backs of the chicks or is one side enough? As for when they grow. I planned to raise the cave on bricks or blocks as others have. It is still somewhat pliable as well. Given these details do u think it still requires revamping?

I followed others advice regarding making one side slightly higher then the other. But one side is definitely low enough to touch the backs and registers at over 90 degrees on the surface

binder clips all along edges

But will the frame hold up two or three-week old chicks playing on it without it collapsing? if you also doubled the hardware cloth on the top, maybe it will be strong enough.

Are you planning on placing the pad on the top of the frame or under the frame so metal doesn't come into contact with the chicks? I like to place the pad under the frame and secure it with bungie cords to keep it from sagging. Then i place a towel over the top of the pad to keep it clean. The shiny stuff is a Mylar space blanket to maximize heat transference.

It appeared it could hold when i out weight on it, but it could easily be doubled as needed. Am i understanding that the metal frame should not be on the underside? Ita confusing when people seem to be doing it different ways. I will put the pad on the underside if ive understood wrong. I thought thats what i had read before but if its bad for the chicks i want to know. Thanks!

Putting the pad on the underside of the frame just makes for a softer surface for the chicks. Probably more people place the pad on top of the frame because it's just simpler to fasten it, hence the paper clips mentioned by one poster. You have the choice to do it either way. It's a personal preference.That's all. One isn't "right" while the other is "wrong".

Either way you choose, the critical thing is to make it secure so a chick can't get itself trapped in the thing somewhere. That's why a lot of folks assemble the pad to the frame and then encase the entire thing in a pillow case so it's wrapped up tight.

I believe you have all the basics covered, and now you only need to fine-tune it. Great job!

Ahh got it! Just wanted to make sure it wouldn't hurt the chicks somehow...i will be fine tuning this week. Thanks!