Despite this weather my chickens, 3 RIR's, have been giving us plenty of eggs. Production slowed down to about 1 or 2 a day since we hit the minus zero temps at night for the last 4 nights in a row, to be expected. Today we got an egg that was a lighter brown and slightly darker brown on the tip. When I went to put it into the carton I rubbed my finger lightly over the discolored part and it cracked. Is this because my chickens need more calcium in their diet? We have noticed the shells being slightly thinner so we did just buy Oyster Shell for them and just gave it to them today, as instructed mixed in with their food. My little monsters picked all the Oyster Shell out of the food container and left the food pellets! Now I am worried they will have too much calcium! Is that possible? and what will happen? For now on I will just throw some on the floor of the run, didn't expect them to do that.....