I didn't collect for any specific time frame. I put in what eggs I had when I was hatching Icelandic and/or bantam Cochin. The one black and white girls lays a large to extra large egg and it is a far deeper brown than that of the other 4. It is almost as dark as a Marnas' egg.
Looking back at my hatch chart, I am getting better than I thought. I compute on viable eggs into the hatcher, not eggs into the incubator. I got 41%, 50%,91%,73% and 67%. Hatched out 31 chicks.'
A client hatched out 3 for me and I got them back.
I quit incubating as I figured that was enough to work with.
I did break open 3 eggs from my black and white eggs and all 3 were fertile.
Now the Erm are free ranging almost every day and there seems to be a bit of hanky panky going on with one of my Icelandic roosters. The Icelandic pens are released on a rotating basis as I am still collecting their eggs for shipment.
Really looking forward to the development of these chicks to see how many "keepers" I get. Get lots of compliments on my adults and people are wanting "culls". Looks like I may have 3 or 4 excess black and white cockerels to make trios out of.