Hello and Welcome To BYC! Sorry you need to place your hens, you might want to post in the Colorado state thread for the best chance of finding them local homes https://www.backyardchickens.com/t/68894/colorado When you have 20 posts you can also put up a Sale ad in the BYC Buy Sell Trade forum https://www.backyardchickens.com/f/67/buy-sell-trade
Chickens can lay eggs for quite a while, but they will lay fewer and fewer eggs as they get older, the general rule of thumb is that a chicken will lay about half the number of eggs at age five as it did at age one, or it will lay about 10% fewer eggs each year after it starts laying. Chickens can live a long time, some breeds live longer than others, but 10 years is not unusual, some people on BYC have mentioned having 14-15 year olds. Good Luck rehoming your girls
I am so sorry you have to give up your birds! What happened? And yes, chickens have been known to live to be 15 years old, although not the norm. I think the average age is 5 to 8 or something like this. My 3 year old Australorp hens are still going strong laying nearly every day. So each breed is different.
Good luck finding them new homes. I hope you can find them a safe forever home.