I've had a great deal of observation over the past couple months and its quite a rainbow when you think about it.
Here's what I've seen from my Turkeys.
Super Green & Runny : They ate a bunch of different wild greens
Greenish & Chunky : A few wild greens, or garden plants plus mostly pellets
Brown & Chunky + Water : Kitchen scraps and bugs
Solid + Water : Random bugs mixed with pellets / Just a hot day
Odd Rusty / Orange & Runny : They found a bunch of bugs and ate mostly them
Orange & Runny & Stinky : Got into some bugs they really like
Perfectly Normal : A cooler day when they just ate pellets
Really Stinky and looks like Oil : Cacel discharge
Might apply to what you see, might not. Either way its oddly interesting and accurate.
So if they were forraging it may mean that they had some insects mixed in. If not, I'm unsure.
Good luck.