Goodness, I hope your girl is okay today! I was not online at all over the weekend...please give us a report. If she's in the same condition, if there's any way you can get a focused, close-up pic of her vent, that might really help. I hate to hear you pushing it back in, if it's in fact not a prolapse...and even if it is a prolapse and it's necrotic, I don't think it ought to be pushed back in, as I think that would cause systemic infection throughout her system. Sorry for rambling, I'm sorta thinking out loud.
Anyway, please do let us know how she's doing today, and please know we've all got high hopes she makes it through okay! You sound like a good chicken momma - and I like that you feel you ought to check them over more closely each day. It's hard to do, especially when you have more than a few. I think they key is a watchful eye. IF you have time to look each over every few days, that's excellent! If not, watch them closely, know who acts like what, where each likes to roost, etc. Then, when you see something amiss in how they're acting, that's a good time to look them over.
Looking forward to hearing from you!