I found with Frosty, she was seemingly randomly getting bouts of the runs, and then it would be one day fast, and two days of boiled chicken and (white) rice. And when I reintroduced the dry food it would be ok for a couple of weeks and then go to pieces again.
Having done a bit of reading of the dog food project - I swapped to a better quality dry food. No more runs (unless she eats something really naughty).
I find she does get the runs if I let her have any bones at all. The bones mess with her inside because she does such a rotten job of chewing them up.
I'm not sure about cooking minced chicken carcasses/bones either, the bone splinters can accumulate in the gut and block it up - this happened to our heeler kelpie x - was expensive to get sorted and mum changed butchers after yelling at him for selliing her chicken mince with bones in it (pet food mince). That butcher no longer in business.
Artemis and Eagle Pack Holistic seem the best of the dry dog food available in Australia. Innovo is supposed to be good - but you can only get it from a chain that supports puppy mills so that no good really. Eukanuba - like the Nutro natural choice chicken rice and oatmeal that I'm currently feeding rates - could do a lot better.
Have a look at the ingredients. Besides the obviously meat product - and it should be specific like beef, chicken meat not meal... shouldn't have corn product or beet pulp etc.
Dog Food Analysis - Reviews of kibble
note above is an American site - and the ingredients and quality control are different when the product is made (under licence to USA) here in Australia.
It may be that your dogs are allergic to chicken or the fat is too high.
I don't feed Frosty bones much anymore. I sometimes feed her beef marrow bones (shin blessed), but I have to stay with her until she's eaten all the easy bits and take it away when she starts chomping on the main shaft bone - because she swallows it in big spikey chunks which come back to haunt us later at both ends.
Instead - for her teeth - I feed her carrots, beef chips (little slithers of rawhide chew), carob pods (not more than one chip or pod a day ideally). And she likes chewing sticks and for some reason - no splinter problems with them.
I don't know why the chicken bits would be ok for so long and suddenly not ok. Maybe your source changed changed suppliers at that time? Maybe try organic chicken wings as an experiment to see if it has to do with the quality. Organic requires strict standards of chicken care like free range / barn raised should but doesn't.