Flower you have got to put all of this down for others to see and learn from. You need a blog!The tan egg layer inherited two recessive white egg shell genes from the parents, plus a small amount of brown coating.
Say your parent birds had Bw, Bw (both these would lay blue eggs) but your chicks could have BB, BW and ww genes for color.
B w
B BB Bw
w Bw ww
75% would lay blue eggs
25% would lay white eggs
BB, Bw = Blue eggs
ww = white eggs