If you're not too happy about adding Biotics, you could try just a spoonful of normal plain yoghurt, its a more natural approach perhaps. I'd agree also with just adding additional things one at a time, it makes it easier to determine what can be tolerated or what not.
Don't get too worried about raw feeding, there's so much information out there that it does appear very daunting at first - I got myself into a bit of a lather quite honestly but its actually very simple and very natural and not as complicated as a lot of the feeding "experts" like to make it. (We don't spend hours every day wondering whether our own diet it perfectly balanced on a daily basis!) and once you get into it, it will run like clockwork! If I can give you advice, it would be to find One good reliable source of information and then stick to that plan, the more you read and research the more confused you get, (been there, done it, got the video!). Best advice I've ever had is from people on here!! Best of luck! (Sorry, Archiebean's comment has just come in as I write, - wasn't suggesting you don't look at her suggested link!😉)