What does it mean when pigeons crave redstone grit?

[LamarshFish]

I feed my homers a mix of redstone grit and seaweed grit (which is mostly sea shells and other calcium and iodine minerals). In the past, my birds seemed to prefer the seaweed grit--they'd pick the seaweed grit out and leave the redstone grit for last or not even use the redstone grit at all. This has been the case for years. When I mix the two grits I do about 75% seaweed grit and 25% redstone.

For the last few months, for reasons unknown, their preference has flipped. They're devouring the redstone grit immediately, and leaving the seaweed grit. I've changed the ratio to include way more redstone. They're eating so much of it that their poop is reddish maroon in color.

I'm just curious why that might have happened? What minerals are in redstone grit that are not in other grit that is making them want it so much?

 

[NatJ]

For the last few months, for reasons unknown, their preference has flipped. They're devouring the redstone grit immediately, and leaving the seaweed grit. I've changed the ratio to include way more redstone. They're eating so much of it that their poop is reddish maroon in color.

I'm just curious why that might have happened? What minerals are in redstone grit that are not in other grit that is making them want it so much?

I have a chicken background, with no actual pigeon experience, but I wonder:

Did the size of the redstone grit change? If the pieces are smaller, they might be going right through the pigeons (colored poop) instead of staying in the gizzard to grind up food. That would leave the pigeons "needing" more grit, because it did not stay in the gizzard and do its job.

 

[prin23]

Did you change brands or open a new bag of the red stone? I’ve found my pigeons go crazy for the red stone when it a brand or a batch that’s more salty, to where I need to really limit it or they wouldn’t stop.

 

[LamarshFish]

Did the size of the redstone grit change?

No, same stuff. And the size of the grit is pretty uniform, and it's made for pigeons.