After the little problem we had with some soft shells a few weeks back and taking on board the advice from this forum, It all now seems to be Ok and we have not had any soft shell eggs for at least 2 weeks.
I now only feed them Layer pellets in the morning, midday its scraps with egg shells and late afternoon its corn.
I went to the Farmers shop in Cross hands business Park (who are brilliant, very helpful & reasonable prices) I went to buy some limestone flour or Oystershell and although they had it it stock, they talked me out of buying any, and recommended just to buy the grit, and if there is then a problem to then try the other stuff and so far no complaints the eggs are great
Woody
