Comb

[falcon3]

Just wondered if anyone would be able to stop me panicking. One of my hybrids comb has gone from a beautiful vivid red to a dark almost black colour. The other two have started to go the same way and im at a loss as to what is causing it. Two are still laying but the one that has gone black has stopped .. I have looked around my garden which they have been freen ranging once out of their coop every morning for the last year with no problems,to see if they have eaten anything unusual but there is nothing different in the garden. Any suggestions would be very appreciated.
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