Hi there and thanks for the extra information.
It sounds as though this diarrhoea is quite persistent but it is good that she appears to be well otherwise. As she is keen to eat and drink and there is not any blood present in the faeces this may still be something you can manage at home, although as we always say here, if you are in any doubt you should have her examined by a vet in case there is something underlying.
Starving for 24 hours and then feeding chicken/rice is a good way to settle the tummy, but you might need to do it a little more intensively to really clear things up. When dogs have diarrhoea, their guts struggle to deal with big meals and this can mean that things don't settle, so probably best to starve for another 12hours or so and then go back to chicken and rice but feed tiny meals every few hours rather than just once a day. Once the stools start to firm up then she needs to have at least 3-4 days of normal poo before going back onto her normal food, and then do this gradually over 3-4 days too. Bakers food is quite rich and contains lots of artificial colourings etc so the gut needs to be fully recovered before it can digest this type of food properly.
Also make sure that your dogs worming is up to date.
If things don't settle, then you probably need to talk to your vet and have her examined - she is an older dog so other things could be going on - she may simply need some antibiotics to clear up a bug but it is best to be on the safe side. If she seems off colour, starts vomitting, passing blood or just generally unwell, then have her examined sooner.
I hope this helps,