Oyster Shells Question

[Junkybird]

My hens just started laying a few days ago. Last week we were at the beach and I snagged a 5 gallon bucket of free oyster shells for them. My questions are:

1) do I put the oyster shells in a separate feeder than their feed?
2) how smashed up do I need to get the shells?
3) if I mix it in with the feed, will it hurt the ducks and guineas?

I hammered up a few the other day and placed them in a small tray inside the coop. It was all over the place within minutes. Those silly guineas are so curious!

Thanks in advance

 

[Wynette]

It needs to be fairly small...I think the largest chunk I've seen in my bag of 50# is maybe the size of a pencil eraser or smaller.

I can't speak to ducks or guineas.

Oh, chickens that are laying age should have oyster shell free choice.