What makes you think she has hyper keratosis?
The leafy part of celery is fine now and then if she likes it. May not be the most nutritious thing going but it won't hurt. Now the celery itself..is mostly water and will cause runny poops.
My 2 love crushed red pepper too(stuff you would sprinkle on pizza) and it's good for them, high in that vit A you are looking for
. It should be pretty easy to find in the spice isle. Something else you could look for in the spice isle is fennel seed and anise seed. You can add those to your seed mix too.
Oh, fresh parsley or parsley flakes(you can add to seed mix) are fine too.
You really should check out that myspicesage.com Chuckie. The beet powder and carrot powder they have there is a great way to sneak veggies right in to her seed mix
Here is another site you might be interested in.http://www.bulkherbstore.com/Herbs
on this one if you click on a certain product it will give a description of the benefits of that herb or spice.
Even if you don't buy from there it will give you an idea of what is what.
They do have quite a variety of good stuff tho