Well, we have a 15 year old large dog, whom we used to refer to as a "garbage disposal unit with fur", who has IBD now and has to take meds and be fed carefully.
Recently, Max has been in such unexpected good condition for his age that dh decided to take him places - he calls it "checking off the items on Max's Bucket List"
Max did great at the lake for a week, so they made a run for the beach and some cleanup at another place we have. But on that trip, dh left him in the truck to run an errand, and forgot about the bucket of KFC. No kidding. He called and told me Max "ate some chicken, what should I do"? I found out the dog ate the whole bucket, dh estimated at least 7 pieces.
I gave him the number of the vet we know in that town, who told dh that she was less worried about the chicken bones because KFC cooked bones tend to be softer than home cooked chicken bones. And if Max quit eating, had bloody stool, or vomited, to bring him in immediately.
In his case, she said she was more worried that he'd have a pancreatic attack from all that grease. Despite what she said, I was in tears that one of those damned cooked bones would splinter and poke a hole in his bowel or stomach and it would be all over for him; at his age/condition he isn't going to survive surgery. At least, I certainly have read about that happening online; my understanding is that cooked bones splinter easily and poke holes, whereas uncooked bones are softer and don't have the potential to cause as much trouble.
The vet said that if he was fine by day 5, then he was going to be okay. He did vomit one bone, but that is all dh saw (other than 2 earplugs and a round nylon hair band of mine in one of his stools). He was fine on day 5, and the he is still okay now, a couple weeks later. I am simply shaking head over the fact our boy survived consuming a whole bucket of chicken - when he was younger, dh used to feed him "road snacks" of little bits of KFC chicken flesh, but that was pre-IBD and certainly never bones. Maybe eating some KFC before he dies was also on Max's private bucket list, you never know
So those are some symptoms above that you can look for - but call your vet and see what he/she says just to be on the safe side.