comb colour

One of my chickens (goldie) was slightly limp a couple of weeks ago but the limp seems to have disappeared  now.  She seems to be a bit quiet thought. She's not as perky as normal and seems to hang back a bit. She is at the bottom of the pecking order but is eating and drinking ok as far as I can see. What's really worrying me is the colour of her comb. It has gone a darker shade of red. Correct me if I'm wrong, but isnt this a sign that there's a lack of oxygen in her blood? She is laying but every two or three days or so. I'm not sure of her age but I dont think she's as old as the other two. Should I take her to the vet or is there something else I could try first?

Yes but it is getting dark not in a good way. She has been a good layer for some time now and her comb has been that lovely bright red colour you get when they are fit and healthy and laying well. This colour is different, its a lot darker.

a darker colour comb (possibly going tinged with blue) can also be a sign of a lack of vit B (I think). Try a little tiny bit of marmite on toast or get some vitamin and mieral drops to go in her water (you can get small bottles with b vits added from bird pet supplies).

If its any consolation one of my hens (a bluebelle) has had a grey/blue tinge to her comb for the past 3 years!  She's doing fine and is still laying well.

Thanks for all the replies. Will keep you posted as to her condition.