Supplementary feeding for an underweight chick

[Poppy Putentake]

I got some hatchery chicks 8 days ago. One started out underweight and does not seem to be gaining weight at a good rate. On day one, (purchased from feed store), the others were all in the range of 35-40 grams, this one was 29 grams. More than that, during the first 24 hours, all the others added several grams of weight, but this one gained less than one gram. I put out cooked egg yolk for all the chicks the first day, and all the others gobbled it up greedily, but this one got less.
This chick seems to be behaving normally and not sick or lethargic, and usually has food in its crop, but does not seem to be developing as fast as the others. At three days, its weight had only gone from 29 to 34 grams, and at 7 days it was only 43 grams. In my experience, laying pullets from other breeds roughly double their weight during the first week. This one is a Speckled Sussex. Could it be that this breed is just not programmed to grow fast?
(Note: The reason I got an additional chick (see my other thread) at 3 days was concern about losing this one.)
So, what to do? The advice I've seen on this forum is to provide supplemental food like egg yolk. The problem is, I am raising 7 chicks with a broody hen and they all have access to any food I put out. If I try to isolate this one chick for special feeding, it does not eat, but only peeps in distress.

 

[NatJ]

So, what to do? The advice I've seen on this forum is to provide supplemental food like egg yolk. The problem is, I am raising 7 chicks with a broody hen and they all have access to any food I put out. If I try to isolate this one chick for special feeding, it does not eat, but only peeps in distress.

You can provide supplemental food for them all, spread out enough that all the chicks can get some.

If that does not work, maybe take away the other chicks for a few minutes, and give special food to just this one and mamma. That way it could eat without competition, but not be distressed. Then put the other chicks back.

If the other chicks are peeping, the hen probably gets upset, so you might have to move them out of earshot for those few minutes-- like in a box in the garage or house. Just make sure they are safe, and it shouldn't hurt them to yell for a little while.