first time hatcher, need some advice!

[aart]

should I intervene in their fights or should I let them work it out?

That can be a tough call.
Much depends on the flock dynamics and how your space is set up.
I've intervened in a couple hen fights,
they would NOT stop, combs were bleeding and cock couldn't break it up.
Mostly I let them work it out, but I have lots of space and that helps.
Some broodies will surprise and become 'broody fierce' with the whole flock despite their prior status.

 

[Ridgerunner]

I'm wondering how long should I wait to reintegrate mother hen and her chicks with the flock.

I never isolate mine when incubating or when they bring them off of the nest so a different situation from yours. I've had a couple of different broody hens wean their chicks as young as three weeks. That's unusual, I'd say 4 to 9 weeks is more common. Some take care of their chicks even longer.

Usually when they wean them it's instantaneous. The chicks ae totally on their own. I have had a few continue to take care of them during the day but leave them alone at light. I've had a few do the opposite, care for them at night but leave them on their own during the day.

Until she weans them the broody is teaching the others to leave her babies alone. I've never had a hen fail to do that but some people say they have. I want the hen to integrate her chicks for me so I let her and the chicks roam with the flock from Day 1.

After they are weaned they ae still the absolute lowest in the pecking order. Mine avoid the adults day and night so they don't get picked on. Give then as much room as you can, day and night, so the chicks can avoid the adults.

when and how should I put them all together again?

What I'd do is just open the gate when you can observe and let the broody hen take care of that. It may take a while before hey actually get close. What I'd expect is that the rest of the flock, or at least some of them, come over to inspect the chicks. If the broody feels a threat she may attack and make them keep their distance. I'd do that sooner than later to give the broody hen as much time as possible to teach the others to leave them alone.

would be 4 weeks a dangerous age gap?

Not especially. My broody hens have no problems with protecting her babies from other immature chickens. By the time the second broody weans her chicks they should be settled in. I've done this with broody-raised chicks and brooder-raised chicks and it hasn't been a problem. The closest I've seen was when some cockerels around 4 months old showed an interest in a broody hens newly hatched chicks. She really let them have it. Nobody threatens her babies!

But sometimes the broody hens may fight over chicks, even with that much of an age gap. I try to avoid having two broodies with relatively young chicks together. Not because of problems between the chicks but potential problems between broody hens.

should I intervene in their fights or should I let them work it out?

That's your judgment call. Usually what I see is chicken gets too close to her chicks and the broody attacks. The other chicken quickly runs away. That broody hen is scary. She's teaching them to leave her babies alone. I almost never see another chicken even think about actually fighting the broody, when that happens that thought leaves after a second or less. But people I trust on here say they have seen it happen. Nothing is definite with chickens and their behaviors.

 

[BDutch]

I keep my broodies separated now. See not touch if the chicks come out in a few days. I’m not worried about the other chickens. But they free range a few hours every day and we have too many neighbour cats to feel comfortable to open up.

Its just not safe to let chicks free range or have the door to the run + coop open. one cat enters the run quit often. If I confine all chickens to the run their space is okay but limited. And I don’t like to confine to 15m2 run space all day. 15 m2 is a limited space, even with 7 very small bantams.

 

[maceleneo]

thank you all for your precious advices, first day of reintegration went smoothly!

this morning I opened both accesses to the run (from the yard and from the coop) and 3 marans came in, they were really curious about the chicks but not aggressive at all.
number one in pecking order was very polite, number two in pecking order pecked pingu on the head, but seemed more of a ritual than an aggression.
only the lowest marans in pecking order (after her there are only the little araucanas.. and maybe pingu now) showed some harassing attitude: she pecked pingu on the legs a few times, but pingu didn't move and that was all. after that, everyone get back to their business and they spent the rest of the day together almost in peace.
the araucanas never entered in the run (they are scared of pingu), but when pingu came out with the chicks and an araucana happened to be near, pingu assaulted her (completely uncalled for) and the rooster stepped in to protect his little lady, but even him went easy on pingu.
pingu is kind of a coward: when their sisters were around she protected the chicks with her body, but she didn't attack any of them for the simple fact of being too close.
anyway, I was expecting much more drama on the first day, luckily tomorrow is sunday and I'll be able to keep monitoring the situation.

I find very fascinating watching these dynamics and even if I know very little about chickens there are some things that seem to apply to all species: for example that the weaker are often the troublemakers because individuals in a position of power don't feel as easily threatened.

I'm so happy they can stay all together again! my yard is not totally predator-proof, but during the day the dog watch after chickens and during the night they all sleep in predator-proof coops.

I guess the wannabe broody changed her mind, because she spent the whole day outside and she doesn't look nervous anymore... this makes things easier for me.

 

[BDutch]

How beautiful !

I’m a bit jealous. I needed to confine my two broodies to a part of the coop where the chicks are safe. Because if I let my flock (5 hens) free range, I need to leave the door to the run open and we have one mean neighbour cat that comes into the run quit often. This cat even grabs pigeons, so I suppose a chick would be too tempting for her if she sees/hears one.

 

[maceleneo]

I wouldn't feel safe if there were cats around!
there are many predators around here but luckily they are scared of humans and don't like to get too close, especially if they can smell/hear/see the dog.
cats can be dangerous for chicks: they're not scared at all and they know they can fool a dog!
luckily the only cat in the area is mine... and she's not worthy of the name!