One of the most common questions asked by new chicken owners is, what's the difference between grit and shell?  Do I need to feed my baby chicks grit?  Do baby chicks need supplemental oyster shell?

The difference between grit and shell is that grit is just fine gravel.  This has been milled such that it's the right size for your chickens to use in their gizzards.  Chickens don't have teeth to chew their food - it all goes into a pouch called the gizzard.  Chickens swallow small pebbles and bits of rock, which stay in the gizzard.  These help grind up the food inside the gizzard, so that it can be digested farther along the road.

Baby chicks may or may not need grit, depending on what you are feeding them.  Many (I would say "most") commercial chick starter feeds do not need grit.  These are either formulated so that the chicks can grind them up without the use of gizzard stones, or they include grit right inside the crumbles.  Check your package if you are in doubt - it should say something like "no grit needed."

Some chick starter feed does require that you give your chicks grit.  And if you aren't sure, it can't hurt to give them grit even if they don't need it for their food!  Grit is cheap, and well worth the peace of mind.

Be sure to buy a grit that is appropriate for the age of your flock.  There is a special grit sold just for chicks, and another (larger) size for adult chickens.  Baby chicks have correspondingly smaller gizzards, and need a smaller grade of grit.  Baby chick grit is also usually dyed red and flavored with anise, to entice the chicks into eating it.  

When chicken owners say "shell," they mean a calcium supplement.  Usually this takes the form of ground oyster shells.  When a hen is laying eggs, she needs a lot of extra calcium in order to be able to properly build their shells.

A feed which has been customized for laying hens will be labeled "layer mix," and will often include enough supplemental calcium.  However, shell is cheap, and it's well worth the cost to provide some even if their feed already includes extra calcium.  

The risk of not having enough calcium is high.  I know one owner who didn't realize he needed to switch from chick starter to layer feed when his hens began to lay.  One hen had to be put down because the brittle eggshell broke inside her.

Baby chicks do not need supplemental calcium, because they aren't laying eggs yet.  However, a week or two before they are scheduled to start laying eggs, you can set out some shell for them.  Once chicks have grown into pullets and are nearly their full size, they really can't "overdose" on calcium.  The more the better!

New layers will often lay soft shelled eggs, just because their systems aren't quite up to speed.  However, soft shelled eggs and eggs with no shell can also be a sign of calcium deficiency.  Either way, you should always have a calcium supplement available for your laying hens.