hi everyone, so i have a bunch of bantam chickens, my older birds are doing fine (my breeders) but my youngsters are having some troubles, they range from 4-6 months old, i either hatched or bought as day olds and they were all doing great up until a few weeks ago. they seem very thin, i can feel the breastbone quite easily. a few weeks ago i lost 2 japanese pullets, they had badly distended crops (i posted for advice and got little, i tried the only suggestion which was olive oil and it did nothing, i think the birds starved to death, they were very very thin at the end). i just lost another japanese, she did not have a distended crop at all, but was fairly thin. they have had a bit runnier poo lately, and about a month ago i switched them from chick grower crumble to layer pellets (as i have some adults with them, so was feeding both mixed before, decided to switch to layer for ease as well as they are nearing pol). im wondering if they arent digesting the pellets properly? they are in a 10X20 grass pen (fully enclosed) with a 10' round chicken coop, i have a heat lamp hung (some sleep under it on the floor, a lot perch high up in the coop with no heat) they have been active and normal looking other than being thin and the now runny poo, so im trying to figure out what is going on. any help appreciated! im thinking coccidiosis (sp?) may be a possibility? worms? as these are unvaccinated birds seeing as i hatched or bought locally. i also took some of my birds (a few of these young ones to) to a local fair show 5 weeks ago, could have picked up something?