Leaving certain food and fossils?

[Zoopism]

Hello everyone!
Zig is quite the eater but she won't eat the 'kibbly' bits of food (see picture). My last hamster ate everything, but not Zig!
I give her Wagg- hamster, gerbil, mouse munch, but I have got new food (muesli mix for hamsters - Wilko) which doesn't have any of the ones she doesn't eat.
Is she missing out on anything by not eating the 'kibble' bits?

Also, I have heard that you can put rocks in the cage to help keep hamsters nails trimmed. On the other photo, I have a pebble (is that suitable?) And also a part of an amonite fossil that I found long ago (the shape would fit well in the cage!)

Zoop

[SinNyx]

Not sure about the food - I feed mine Harry Hamster and some are picky, but if you try not feeding as often then they may start to eat the pellets, but hamsters have their favourites, same as humans

With the pebbles, I'm not sure how big it is from the picture, but I wouldn't give it to mine in case they pouch it. I used large stones in my cages for the hamsters to wear their nails down, usually I put it below the water bottle or as a step up to something so they use it. If it's not big enough for them to really sit on, I don't think it's worth it as I can't imagine them walking over it enough to help

[evel_lin]

I use bendy bridges and bog wood in cages to give them something to climb over and wear their claws down. I've also got sandbaths as well. I think normal digging and running around probably wears their claws down enough anyway, the only time one of mine had long claws was my hybrid Oak and he was very old and wobbly so didn't really run around much

[NiceCrocs]

You wanna give them big stones, that they can walk and climb on. The one I use is about ten inches long. It's hard to tell from the pic, but the ones you have look like small pocket stones. If so, they'd be useless for nails; the hamster would be more likely to try and chew it or pouch it, which would be bad.

ETA: terra cotta dishes work really well too; the kind you buy a garden stores and put under plant pots.

[Zoopism]

Thanks for the advice the pebble is about 5cm but I think I should get a bigger one or a terracotta plate! Thank you!
Zoop