I would definitely give everyone probiotics everyday. They are fine to give & REALLY good for the gizzard. As in humans, bird GI tract is the 1st line of immune defense. So if there is a good supply of the good bacteria there, your chickens will have a head start on being healthy & be able to better digest the nutrients they need from their food. I agree with only giving the hen that is laying soft shell/shell-less eggs the extra calcium. Make sure she gets plenty of sunshine to activate the vitamin D, so the calcium is absorbed.I didn't know if probiotics were ok every day but now that I know they are, I'll be giving them a pill in the water every day or in their wet food that they gobble up in a few minutes so I know they'll be getting it all. I'm going to give just the one some calcium not all of them. They do always have oyster shell out there but prefer the real shells crushed up. I just can't keep enough out there of that for them. I was actually thinking of going to a bakery and asking them to save me shells one day a week so I could give them to the girls. They probably go through dozens a day!
I'm going to read about amino acids concentrate... never looked into that before.
Thanks for the help everyone!!
It's definitely a good idea to see if there is a bakery who you can get shells from, but oyster shells have more calcium than egg shells.
If you decide to get the amino acids, I would treat your feather picker and your one with the egg issues. Both can be caused by nutritional issues.