I also got 6 ex-batts about the same time as you. 4 of them are looking fantastic but the other 2 still have bald patches. I've noticed that as soon as an area looks like an un-shaved chin (on a fella!) then it's only about a week or so before the feathers come through. The "baldies" are so loving, and 1 of them is definitely the big bossof the flock. Don't worry, time and patience I think are the answer