Chicken laying eggs with no shell

[ChickenOfSpades]

I have four chickens. They have all about reached 18 weeks. I've found two "eggs" in the area they like to roam around during the day without a shell. Looks like a yolk and maybe a sack.

The barred rock has laid several (~7) little normal eggs over the last 10-14 days...small but otherwise normal. So I can probably rule out this chicken.

The other three are a Buff Orpington, Red-Laced Blue Wyandotte, and an Australorp. Not sure which one it is yet.

Here's a photo of the one I found today:

I've been gradually switching them from grower feed to Purina layer crumbles with calcium (https://shop.purinamills.com/products/purina-layena-crumbles). I'm going to pick up more oyster shell supplement in the morning.

Is there anything else I should be doing? They've all seemed otherwise very active, happy, and healthy.

Thanks!

 

[_-Captain BRM-_]

Lack of calcium, sometimes it's also caused by a new layer of younger hen. Not a big deal, just be sure that they have more calcium in their diet, looks like your already doing that though.

 

[ChickenOfSpades]

Lack of calcium, sometimes it's also caused by a new layer of younger hen. Not a big deal, just be sure that they have more calcium in their diet, looks like your already doing that though.

Brand new layer. Probably her first two eggs ever. I'll make sure they have plenty of calcium and see if that fixes it. Thanks!