Brooder is ready for chicks! Any last minute suggestion please. (Photos)

25 duel purpose pullets are arriving (hopefully) in the morning. I used a corner hay rack as the cave, covered it in hardware cloth and put tape over any sharp edges. I stuffed the corners with straw, covered with one towel, then the heating pad and one more towel. My oven thermometer is missing, what level you keep the heating pad to keep the temp at 100? I have the sunbeam with no auto shut off, it has 6 heat settings.
Thank you everyone for helping me get to this point. Hope I'm ready to just add chickens

It may be too low but you'll have to play it by ear. If they don't go under it, it's too low. If they stay under it all the time, it's possibly but not necessarily too high.

The feeder may have to be set up on something. They love to scratch bedding and feces into it.

Since they're coming as day olds, they don't know what water and food are. I would put a water fount in with them to make sure they all get hydrated and are vigorous before you make them rely on nipples.
The same goes for food but not as critical as water.

Thank you. I originally thought it would be too low and have some strips of stall mat to raise it with if needed. Once I finished it and was sticking my arm under it to see how well it was heating I was surprised at how much room there was under there. When I had asked on a previous thread what the interior height of the cave should be it was mentioned that the chicks backs should be able to touch the top although for day olds I think it's higher than that. I also have a larger rectangular hay feeder that sits much higher off the ground that would work well for larger chicks.
Generally how long do chicks need a heat source for? We are in the mountains and have temps in the 70s during the day and 50s at night.

I've been doing what you're doing. I get my new chicks in the morning.

I set the heating pad up on my garage work bench and turned it to the highest setting, #6, and left it for a bit. I stuck a thermometer under it, and got a reading of over 100F. (I need to add five degrees to a mercury thermometer since I'm at extremely high altitude). I turned it down to #5 and got 90F.

Later I took it outside to the run and set it up in the chick pen and turned it on to #6. Stuck the mercury thermometer under it and got 85F.

Last summer, this time of spring by the way, it was 30s at night and not over 50F during the day, so I had the pad on #6 at night and turned it down during the day. This year has been ten degrees warmer day, as well as night. But I'll probably still start the chicks out on the highest setting and see what happens.

Anyway, your setup looks terrific! Glad you're going with the MHP system! You and your chicks will love it! By the way, if you haven't already heard, you need to make sure, due to the large number you're brooding, to open the back as well as the front of the cave so chicks don't get piled on and suffocated. That was an issue with large broods as people have been testing this system all this past year.

You're question about how long chicks need the heat source is a common one. Chicks lose body heat as long as they only have down. As they grow in feathers, they need less and less heat since they're becoming insulated and retain body heat better, until they need no heat at all by the time they fully feather out. Chicks brooded outdoors are feathering out completely much sooner than indoor brooded chicks, so don't be surprised if you see your chicks avoiding the cave during the day at the end of two weeks, and no longer sleeping under it by the fourth week. When you see they no longer are sleeping under it at night, you can remove the heating pad cave and start teaching them to roost in the coop.

Thank you Azygous.
I can't open up the back of the cave because the hay rack is flush with the floor in the back. I stuffed the short side with straw so no one could get stuck back where it's very very low. I originally tried to make one out of hardware cloth that was open on two sides, but the top was too weak and kept drooping so I decided to use the hay rack as a frame. The heat source is towards the entrance of the cave, but now you have me worried that I could lose some to suffocation. There is a decent amount of room in there, but only one exit. I do have a much roomier hay rack, it is significantly taller, but I could build up the shavings inside the cave so they are closer to the heat source? I put a pick of the larger "frame" in a separate post.

Had the hardes time getting these to post. Wouldn't let me put photos in until I went into to edit. Oh well, this is the larger hay rack. I could leave the back open and build the ground up under it so they are closer to the heat maybe.

Building the bedding up would work. I've never brooded more than eight chicks, and usually it's four on average, so I've never had the problem of piling and crowding. But large broods will do that. They can be like a herd of wild horses, getting spooked at the slightest thing and they pile up and then you go out there in the morning and find a couple dead chicks and wonder what happened. Chicks can be downright suicidal and you don't want to make it easy for them to do themselves in.

That hay rack has perfect contours for a MHP cave. You should go cross post on Blooie's thread and show them that. They will love that idea over there!

How about not taking the hardware mesh all the way down to the bottom on the sides? Leave two inches of space in case chicks crowd and pile. That way the ones at the back may get squeezed out the sides instead of trapped. And I would encase the entire frame in a pillow case so chicks can't find their way into the overlap of your hardware mesh and get injured or die. It's yet another way we've all seen the occasional chick suicide from the MHP frame this past year. So we recommend leaving no metal parts exposed. Once you slip the pillow case or other covering over the metal frame, you can get those tiny bungies and secure it in place. Some of us then stick a layer of Glad Press 'n Seal over the top, making it easy to clean the poop off. In fact it will usually just brush off unless there's a cecal smearing the works. Details.

I also like to secure the heating pad to the inside of the frame with bungies. It makes a much better contact with the heating pad for the chicks than if you lay the pad over the top of the frame.

Ok, I will make a new cave out of the larger hay rack and build up the bedding until it's the right height. That had been my original plan, but the more I looked at other peoples caves the more I worried it was just too big.
If I want to make it so there is an open area at the back and sides won't the pillow case cover those exits? And how do you prevent it from drooping?
Right now I have the hardware cloth attached to the frame with little pieces of wire that I covered with tape, it's pretty secure.
I suppose I could snip holes in the pillow case and still use wire to attach it. And even if the back exit is blocked I should be able to leave a little space on the sides.
Sorry if I'm not "getting it", I'm not quite awake yet.

If the pillow case is loose and "flappy" on the sides with a little bit of daylight able to get in, any chicks that become victims of sudden piling and crowding would be "squirted" out the loose sides since the wire doesn't come all the way down. In theory anyway. Are you using the larger model Sunbeam pad? If not, you may need two regular size pads of adequate heat coverage.

Remember, the concept of MHP is direct contact, not an oven effect.

I'm on my way to pick up my new chicks now, fifty miles away across the New Mexico prairie.

I still urge you to visit Blooie's thread and let them see your set-up. Lots of fine brains over there. Someone may see something you and I aren't that could make your system even better.