Unfortunately, feed will not have an effect on internal laying, not in any appreciable way. Other than one study regarding the benefit of flax seed in
possibly staving off internal laying in some cases, there is no evidence that any food, supplement, vitamin or mineral will stop it from happening. Internal laying is a genetic/hormone based malfunction. Mine had the best food, the best surroundings, the best of everything in every way *including flax seed*, but the ones who suffered from this were all my common hatchery stock (all except for one, and her mother was a hatchery hen). The breeder stock seems to be made of stronger genetic stuff.
Of course, the hens who have the best immune systems and are in the best all round health when this happens may be able to live longer, like my Ivy and my Olivia did, but eventually, they will succumb to it. I hate being the bearer of bad tidings; it's just that I have done so much research on the subject, consulted with very knowledgeable and educated folks about it after having it happen with one after the other, and it always comes down to the same conclusion. When they have fluid buildup in the abdomen as Olivia did, you can at least feel you're doing something when you drain it, but not all of them have any palpable foreign body or fluid in the abdomen you can even deal with.
Just keep loving them and caring for them. These hens are fortunate that they have owners who are so concerned with their welfare.