ok, here's a dues payment.
First, yesterday two things happened to the hoop coop before I got the chicks (thankfully):
a critter dug a hole under and into the coop even though we laid a fence apron of welded wire fencing 2"x4" :
so a run to the feed store and 100 feet of hardware cloth (ouch) and installation in the dusk. While the feed store run was happening, up came a storm and away went the tarps. See why I am so glad the chicks weren't there yet?
Here's the hoop coop - the billboard tarp turned out to be half the length promised, so making do with an old leaky brown tarp:
last night, worried about the chicks getting trapped into the grate somehow, so found some fabric and wrapped the whole 4 foot long grate with pad and used clothespins and bungee cords. ONly trouble is, I will have to unwrap the whole thing to adjust the bolts for height...
You can see teeny feet under the MHP :
and yes, with 4 feet there should be enough room for the 25 chicks. The pic was taken about an hour after I put them in the brooder. Some of the chicks still have their egg tooth, some are starting wing feathers.....
and here is a pic from overhead:
the base of the brooder is a 4x4 maple sugaring pan. Because the grate used for the MHP is also 4', I had to put it at a diagonal to fit it in. There are feeders and waters on both sides of the MHP .
Only thing is, I can't see all the chicks no matter what. About an hour after putting them all in, they were all under at the same time for about 2 minutes. I spent the first hours putting any sleepy chicks back under because I wasn't sure they all understood it was warm under there. I've seen some go in and out on their own. Eating and drinking and sleeping - happy chicks!
Thanks to everyone for all the posts, comments, suggestions, etc.