2 chickens with purple tips on their combs---question

[krv]

My son has 5 leghorn hens that are about 1 year and 2 months. We just bought them from someone about a week ago. My son just noticed 2 hens with purple tips on their combs. The others don't have the purple tips. The 2 hens also want to lay down and sleep some during the day, but the others do too. The 2 mentioned are not coughing or making any sickly sounds. Is this normal? If not, what can we do?
krv

 

[LuannKeller]

Stress can darken the comb. Heat can cause enough stress to dark the comb, but you should also check them for parasites. Make sure they don't feel thin and that their breathing sounds okay.

I had a little fellow who had a terrible case of mites although his friends did not (he was a watcher, not a dust bather) and his comb turned purple. I treated the pests and gave him a teaspoon of honey and within the hour his comb was red again and he was up looking for something to eat. He's fine now.

 

[key west chick]

Don't know where you live but could it be frost bite? My roo has several tips missing off his comb.

 

[warren]

One of my hens is nearly 3 years old and the back of her comb goes purple when she gets excited. It goes red again later. I think it is just circulation in her case. I wonder if hens get angina?