Chickens have "the squirts" with white, runny poo

[Lyris]

I realized today that the favorite chicken hangout areas in my yard are covered in white, runny poops. Lately I've been leaving for work before the chickens get out and don't get home until they go home so I don't know how long it's been going on. Since it's my day off I was able to monitor and see what's going on. At least two of them have pressurized liquid poops that make my cat's farts seem tame. One has a very goopy butt, another is developing a goopy butt, and a third may have had a goopy butt, but now it's bald and red (I think from molting). Two of them are feeling under the weather today as well. I had to coax them to eat, but they perked up a bit once they had food. One of the goopy butts seems a bit thirstier than the others, but otherwise seems fine.
The only difference I can think of is that they've had probiotics in their water for a recurring respiratory illness. I don't know if they began having issues before or after that, though. I've switched them back to regular water just in case. They've never had poop problems with the respiratory illness so I'm guessing that's unrelated. They're also going through a very hard molt at the moment. Their current diet is mostly the stupid amount of bacon/eggs/sausage I get from work every day and whatever they find in the yard, though they do have access to pellets.
Ideas what it could be? The probiotics? Something from the yard? The respiratory illness?

 

[Eggcessive]

Do they get any balanced chicken feed, layer or all flock feed?

 

[Lyris]

Do they get any balanced chicken feed, layer or all flock feed?

Before they were on an all flock feed since my rooster is particularly sensitive to high protein (he has heart issues). With them molting I just switched to a 20% protein pellet that they've had before. I don't have the previous bag, but the current one they're on is from Kalmbach.
They were briefly out for a few days while I waited for my paycheck, but I made sure they got extra eggs/sausage. They weren't particularly interested in the pellets when I got them again. I had to turn them into a mash to convince them to have some.