Well the cats should be fine with adult birds but the sounds of babies really brings out the natural hunting instincts in the adult cats.

If your free ranging and supplying additional feed no need to worry about laying feed and oyster shell until they actually start laying eggs. They should be healthy enough on what they are getting. I know my hens and roos love the cat food too which is high in protein and good for the layers.

Roberta,

What I do when I have a mess of chicks is wait until the first egg or two starts to appear. Then you can start the layer rations. We also offer a mix of standard grit and oyster shell on the side.

Cats and chickens do co-exist (to my initial amazement). Just keep young chicks away from the cats as this just might be a tad too tempting.

And yes, throw them a handful of cheap cat food especially during the summer when their protein intake is down. The will love it and it's good for them in small amounts.

Mike in TN

There should be sufficient calcium in commercial feed. You don't have to give them oyster shell. Mine never get it and don't have shell problems. I start layer pellets at 16 weeks.