You probably already know this but some people are sensitive to the histamines in bone broth. You can start with a very short cook, no more than 3 hours (as recommended by Dr Natasha Campbell-McBride, who wrote Gut & Psychology Syndrome for gut healing). Or even more easily digestible is to start with a meat stock, and build up to bone broths. Basically you just stew up some meat, and drink the juice.