Ok. Maybe I'm still just worrying but the runt of four 3 1/2 week old ISA browns is less than 1/2 the size of the others and since yesterday she seems to be acting a little funny. It's hard to tell but she seems to be sleepy more, eating less (or at least being seen to eat less) and chirping more. When I take them all out to be handled she seems fine and wil eat oatmeal vigourously from my hand but something seems amiss. It is cooler in the studio where the brooder is but the heat lamp is on in one corner. Any ideas of what this might be?