They are not dead but they certainly look stressed!! I am not certain what the cause may be but I doubt that they are going through an early dormancy. In my zone (very similar to yours), bigleaf hydrangeas look much the same as your first plant - leaves intact and still a glossy green, although any flowers have begun to fade. They will not begin to go dormant (shriveled, blackened or dropping leaves) until after a hard frost, which may not show up here for another 6-8 weeks.

Could it be that the two that are looking poorly just did not receive adequate water earlier?

Yea that is all I can think. There is a concrete walkway in front but my house is on stilts so there is ground all underneath and behind that lattice wall you see in the picture. My other hydrangeas look just like the “good” one I posted. I’m assuming water is the issue. Will the branches all bloom out next year or will next year it be a small bush and have to grow from the ground again? I see buds on the branches.

Make sure they get plenty of water going into winter (but don't flood them :-)) And I'd wait until spring and the shrubs start budding out to see what happens. If there are buds present on the stems now, chances are good there will be some as well in spring. You can make the decision to leave or remove at that time. So it's a bit hard to predict what the shrub will look like then or how it will behave but I'd be prepared for these to show some sort of need to regrow from the base.

Thanks, I’ll keep up with better watering on these.

I would add to make sure that they get evenly moist soil, especially in the Summer. I suspect that they are going through periods where they dried up too much but then received water then dried up again, etc. Once conditions improve water-wise, they may leaf out or leave that until Spring (assuming the ends have not dried out permanently). In that case, in Spring you will get leaf out thru part of the stem (the bottom) and the rest will remain as it looks now. If that part does not leaf out by the end of May then it will not leaf out for sure and you can prune the dead part away.

It is kind of early for dormancy here, not sure about you but, I will be visiting relatives soon and may notice something next month.

Would it help to take them out of the ground over the winter and use some type of peat moss or manure or anything to help the soil next year?

That would very likely retard any development further.....they will be much happier in the ground. You can mulch now with compost if you like - it won't hurt and it can help, sometimes a lot!!

Sorry I just read my post, I meant take them out and repent them using peat moss or something else to help retain moisture during the next summer. I wasn’t meaning to keep them in a pot all winter.

No, just try to remember to water them as appropriate in Summer. If you use computers/smartphones, try to set up electronic reminders on a certain schedule saying to go check the soil to see if it needs to be watered. Or highlight c3ertain days (say in blue for water?) to remind you to check the shrubs' soil moisture. Mulch and organic compost hold a lot of water but you do have to replenish it biw and then. If you have difficulty with that, consider moving them to another location where all or most of the water hungry shrubs are located and where you may "see" them and water them more "accurately".

I’ve had hydrangeas that just weren’t thriving like yours, and in subsequent years despite good care, they never took off. So while they are not dead, you can give them a few more years if you wish, but in the end I have always ended up scraping them and starting over due to failure to perform.

"I meant take them out and replant them using peat moss or something else to help retain moisture during the next summer."

No, disturbing the roots to that degree would hurt more than help. Just topdress with compost regularly and your soil will improve. Keep mulch on them and when you water them do it slowly and deeply such as with a hose on a slow trickle. Water needs to penetrate deeply, not run off or get blasted.