12 hours ago, chromedome said:I do it with bone-in frozen rabbit and chicken. [...] Bottom line, there's no particular reason not to.
Well, I found a reason not to, at least for me.
When I make stock, I always parboil the chicken and rinse the pieces under running water before starting the actual stock-making process. All sorts of debris and junk are cleaned from and from and, to a degree, from within the chicken.
By putting the chicken into the IP frozen, without parboiling, the stock was somewhat (a little) murky and had a somewhat less-than-clean-and-fresh taste compared to the stock from non-frozen and parboiled chicken. It'll be OK for some recipes, but for others only non-frozen and parboiled chicken will be satisfactory. For example, putting the stock into a heavily-flavored chili should be OK, but tomorrow I'm going to cook up some chickpeas in the chicken stock for use in a couple of chickpea-forward dishes and I'm concerned about the results. I'll post my findings when that's done.
So, while the experimenting isn't complete, I am sure that going forward I won't be cooking chicken in the IP directly from frozen. However, it's nice to know it can be done with reasonable results, but I can't think of any reason to do it other than having a time constraint.