Purina Layena Feed plus extra items

[Titan Farm]

I feed flockraiser to my ducks and chickens and then just add free access to oyster shells. The reason being that
A. I'm not paying full feed prices for feed with added grit and oyster shell. Oyster shells are cheap cheap cheap so I can buy a 50lb bag for $12 that lasts me almost a year and when I buy their feed I'm buying 50lbs of actual feed.

B. Grit they can get from the ground when they forage and if they really need it I will go dig up some gravel from the driveway.

C. I don't want to pay for something they can get for free. So when you buy that Layer complete you're paying money for grit and oyster shell and not getting as much feed in your bag.

D. I prefer to let the hens decide how much calcium they need by eating the oyster shell separately. Less chance of overtaxing their kidneys with excess calcium.

To my knowledge none of the larger feed Mfg adds grit or oyster shells to there feed.
There is no need for the grit and the main calcium source that is added poultry is calcium carbonate, ground limestone or a combination of the two.
Now there may be a feed Mfg out there that combines some oyster shells in with there calcium carbonate or ground limestone but there would be very little added just because calcium carbonate and ground limestone are cheaper than oyster shells and it accomplishes the same thing.

 

[GC-Raptor]

My tag for Purina Layena plus Omega 3, has Calcium Carbonate as #4 ingredient, and Oyster Shell as #7. Purina adds oyster shell to their Layena feeds. The only company that I know of. There is no grit in the ingredients on this tag.
I also have a tag from Nutrena Naturewise Hearty Hen (Soy free), Calcium Carbonate is #5 and no oyster shell or grit listed on tag. GC

 

[Titan Farm]

I wonder if that's Purina's new gimmick?
I just read something on there page about how there adding oyster shells and they clam that oyster shells have a larger particle size than limestone and that why there adding it to there feed now.

Well to me there clam is a sales pitch, limestone can come in the same particle size as oyster shells and some studies state that the strength of a hens egg shell is the same weather limestone is used or oyster shells used as long as the particle size is the same BUT when a bone strength test was done on the hens it showed that the bones were stronger on the hens that had limestone instead of oyster shells.