hi,i'm new to this site & only had hens for a few weeks.problem is i've got 4 hens all about 22 weks old now,2 of them were laying regularly,2 not started yet.the 2 that have been laying have now stopped & i don't know why.they free range until dark then go into a secure coop at night,they seem very happy & healthy.feed them on layer pellets with a small amount of corn scattered for a treat,water always there ,bedding kept clean.am i doing anything obviously wrong?feeder is kept topped up.any tips welcome.