We used to give our flock of 10 hens raw milk. They loved it.Have you explained to C and Wendy what the grit and OS are for, so they don't chuck it out? And yes your girls' munching of the greenery is very apparent, as are the potholesBut you're not dealing with birds depending entirely on foraging, which is of course the extreme case, and I was thinking of the distinction made in many of the old poultry manuals I've read between production rations and maintenance rations, and at this time of year, with little to no laying, they'd be on maintenance rations. Also, your comment about production breeds needing a production diet seems to go against the grain of much of the earlier discussion about whether and to what extent the rescues are a breed apart from 'normal' chickens, so to speak.
Also, those old books (i.e. written before the invention of commercial chicken feed) usually supplied the calcium (and a good dose of protein) via dairy products, which were produced on the farm of course. So perhaps you could just take more milk than you need for your thermos of tea and share it with them...![]()