-Whats the best way to mark the fertile eggs so they dont get mixed up with daily egg gathering?
I use a black Sharpie and make a circle around the egg so I can see the mark no matter how the egg is laying. If you are setting under two different hens, you might want to mark them differently so you know which egg goes where. It's not unheard of for a broody to steal eggs from another. If you start them the same day, this is obviously not as important.
You may hear from people horrified that I would use a Sharpie. They have read that the fumes will kill the chick inside. Obviously I don't believe that, but you can also use a pencil to mark them. Just use a soft leaded pencil. A #2 will work but a #1 is better. Sort of lay the pencil in its side and rub a pretty good line on the egg. If you use a hard leaded pencil, that line is really light and hard to see and can rub off.
-Whats the opinions on leaving hen in coop with other chickens when raising chicks?
Hens have been doing this for thousands of years and chickens are not extinct yet. Anytime you are dealing with living animals, bad things can happen, no matter what you do. I do think that adequate space is important. If the hen raises them with the flock, she will take care of integration issues. I had a broody wean her chicks at 3 weeks of age in the heat of summer and the chicks did OK with the flock. They still had pecking order issues, being at the bottom of the pecking order, but with adequate space, they managed.
If space is tight or you have a history of a hen that is overly aggressive toward the chicks, separation may be in order. But if space is tight, how are you planning on doing integration later?
-Any other advice or learned lessons would be wonderful.
Many people have two broodies hatching at the same time and don't have problems. But there are some things that can happen. I'm not mentioning these to scare you or tell you that you can't do it, but just so you can watch for certain things or maybe be proactive in preventing them.
If you set the eggs at the same time, that removes the problem of one hen stealing the others eggs and you getting a staggered hatch. But if one hen hears the other hen's chicks hatching, she may abandon her eggs and go to the hatching chicks.
Its possible two broodies will fight over the eggs or the chicks. Chicks or eggs can get damaged in these fights. Hens too, for that matter.
Occasionally one broody will kill the other hen’s chicks instead of trying to take them to raise. This can happen whether they are sharing a nest or in two separate nests.
As I said, many people have two hens broody at the same time and don’t have these problems. Often, two broodies can share a nest and hatch together, them work together to raise the chicks. I can’t tell you what will happen, just a few things that might happen.
Good luck!!!