Good questions. I'm not 100% sure but my rule of thumb is if they are acting totally normal, they are probably fine. But I'm also paranoid, so when someone seems to have something wrong, I try to address it ASAP. For example, I noticed one of my EE's crop wasn't emptying at night. She acted totally normal, but I brought her in and treated her for impacted crop. Eventually things seemed to get moving along, so I put her back out with the flock. The entire time she didn't act sick or anything like that, so who knows if it may have developed into something worse.
What you can try with yours is a warm epsom salt bath. My RIR hen was having trouble laying a while back - I could tell she was trying to lay but nothing was happening. I brought her in and gave her an epsom salt bath and ten minutes later, she popped out two eggs into the water (one with a soft shell that broke right away, the other egg kind of wrinkly).
BUT if your girls are egg bound, I've read that it can definitely be bad if things build up. So if that is the issue and it's just not bugging them yet, if you can take care of the problem now, it will be better in the long run. But I'd make sure it's eggs you are feeling. And I'm not sure if the abdomen will be squishy with egg binding (I'm assuming it all depends on how backed up the eggs are, I guess). Anyhoo, hopefully someone with more experience will chime in. Good luck!!!