It should be daily. You can buy a water soluble vitamin blend at your feed store and mix it in all the drinking water. But when you do this it should be changes every 24 hours so don't mix more that they will drink up each day.

In the fall I use store bought high potency B-Complex and dissolve 1 caplet per quart of warm water (110 -120 F). Then add 2 qts of layer crumbles and give to all the hens. It won't hurt the Roos if the get the extra energy boost. Never give individual B vitamins they should always be in the form of B-complex for the fact that they are only used fully if you have many other 'support' vitamins in order to work.

You should be cautioned that if you have a bird that is a diabetic they may develop leg/foot pain/tingling if their B-complex intake is too high. If you notice a bird with difficulty walking or walks with a limp after starting this, chances are they are diabetic and need their B-complex intake reduced. That is about the only problem I have noticed. I now check each bird for diabetes before including them in any breeding program.

Seramas,
Thank you for the explanation. I'll get some B complex when I go to town this week, and start the ladies on their vitamin regimen. I printed out your reply and put it in my "chicken book" with the other valuable information I've picked up from this site.
Sorry I misspelled your post name.