who sells a good chicken salad in baton rouge

Calandro's chicken salad is excellent IMO.

There can be only one

Bocage has a Chicken salad thats more like a dip, very good.
Albertsons on Foster has a nice low mayo chunky style thats very good.

Calvins secret is cream cheese

I like Calvin's chicken salad a lot but it's the exact opposite of what you're looking for if you want chunks, grapes, nuts, etc.

Whole Foods and the place in the market downtown has a good one too (or they did 2 years ago)

All depends on what you're going for.. For the chicken salad that's served as finger food at receptions, on quartered white bread with the crusts removed, you want a chicken salad spread, so the salad chunks aren't falling out of the sandwich and onto your clothes..
For the crusty-bread-sandwich served at home, I'd rather have the salad chock full of walnuts, grapes, apple chicken salad that's more like a salad than a sandwich spread.

Maxwell's Market has a good one too.

just make yor own.

Chicken - buy a roasted hen, boil some tenders in chicken broth with a little celery or buy a can or two of canned breast meat.

cut chicken to your preferred size - I prefer kind'a chunky chunks
chop some sweet pickles - I like more pickles than less, but this is America, so add the amount you like.
chop a stalk or two of celery kind'a fine chop.
chop a little onion if that's your thing (i don't)
put in bowl and add mayo Hellman's

Grind a little fresh black pepper over top before mixing

Add half grapes if you like. Add chopped walnuts or pecans or almonds if you like.

Wife adds craisins (good) and maybe white raisins (OK, too)

We have had it with sunflower seeds and I like that also.

Biggest requirement is Oat Berry Bread on eother side of a big spoonfull smeared to about 1/2 inch thickness and a perfectly chilled cold beer.

Why would you want to go out to buy it, now that you know the truth?

I can start and finish before I can get tto the grocery store and back and know how long it has been sitting there before I eat it.