I'm glad my post was of some use. The answer to your question, as far as I understand, is 'yes' but it's a very conditional affirmative. Anyway, here's my experiences of and opinion on instincts in chickens:
Instincts are bred in and out of chickens according to the environment they are within. If it's just a cage, after a few generations (5 is the average before you can count on 'info being deleted', so to speak) they will lose instinct for surviving outside the cage; they'll do things like not escape a predator, eat non-food or toxic things, etc. Misdirected or unnatural instincts are also bred into them according to which behavior the parents exhibited and still lived to breed on, including cannibalism, killing of injured or ill birds, feather-pecking, bullying, violence, chick-killing, egg-eating, etc, if the environment and keeper allow this to occur.
If they do it once, there's a very good chance they'll do it again, and their offspring might anyway even if they can't do it again. If they do it again, there's almost a guarantee they'll pass it on to some offspring. That's only in the first generation, too. Chickens can suffer from neuroses and mental aberrations as well. If a chook's behavior doesn't kill it, and it perceived some reward for it, it will likely pass it on. This is why culling is the best way to handle severe socially damaging behaviors.
From my observations and social experiments with chickens and other animals --- but when I say experiment it does not mean I harmed the animal --- I believe only a few instincts or automated responses are strongly fixed. These include pecking at food, drinking, getting out of the sun when they feel too hot, being afraid of something large rushing at them, and flapping when falling or off balance. Very basic survival skills. They're not set in stone, and can also be altered, but obviously most which lack those instincts do not manage to pass on their genes. I think everything else on top of those basic instincts is much more malleable, and changes with the environment they are allowed.
When chickens breed, the chicks inherit the parent birds' miasma, and their instinct, which are two separate things. Miasma is the tentative beginnings of instinct, in the way I'm using the term. It's the individual chicken's recording of positive and negative experiences with everything they encountered in the lifetime of that particular bird. It also a record of the reactions of that bird to the stimuli it encountered, which if confirmed/rewarded/ reinforced in its offspring can move from suggestion/inclination to become an increasingly strengthened behavioral pattern these offspring will pass on in turn, whether right or wrong. If this parental miasma is not reinforced in their lifetime, they will in all likelihood only pass on those unconfirmed patterns to half their offspring, and they in turn to half of theirs and so on. (Rough generalizations).
Generally by the 5th generation it's gone if it has not been reinforced. I have no idea why the 5th generation is such a make and break time but it appears to be due to DNA and inheritance and works mathematically so it likely has an actual physical/biological basis. Miasma is like a mental push, a gentle urging to do something. Chickens experiencing the impulses of miasma will often stare at something that's stimulating the ancestral memory, as they try to make up their mind. They're inclined to react a certain way but aren't sure why; the threat or reward is not yet obvious and so they often hesitate. Whatever tips the balance and provokes them to test this idea will then either result in it being confirmed or dismissed. Instinct is something they obey without questioning, or even something they have no control over, but miasma is the chicken's experiment. Agh, lol, such terminology... I hope you know what I mean.
So, if the parent bird knew about being careful to not eat a certain plant at a certain time, and its offspring are allowed to reinforce/confirm this pattern of behavior, then they will pass it on, as will each generation allowed to confirm it, and by the 5th generation or so it is set as something that family line knows for sure. Now it is a strongly heritable instinct. But if you start caging them or remove the plant, before the 5th generation, that miasma or developing instinct dies out quite fast; it kind of fades into a dream for them. If you remove the plant after the 5th generation, then for a good few more generations they'll know without a doubt how to handle that plant if it appears again, even though they go generations without seeing it.
Some behaviors have no visible reward, and others are clearly the result of a damaged mind. Bad behaviors are much harder to breed out than in. Good behaviors are harder to breed in than out, but culling for negative traits brings in good ones quicker, especially if you're providing an environment they can explore and interact with. But in my experience it doesn't all come flooding back, it has to be rediscovered. Bad behaviors we often unwittingly force upon them, but good behaviors we have no such ability to forcibly introduce into their environment. A chicken inclined to be peaceful is a likely bet for producing descendants who rediscover good social instincts, whereas a bully of a chicken is inclined to produce offspring who may be even worse. There is a bent they learn towards and their offspring will often enlarge upon the parent's tendencies.
This is going to sound strange due to the terminology but I hope you understand what I mean. If you take a chook from an ideal free ranging environment, where it's been bred and reared, and put it in a cage for the rest of its life, it will lose some visibility of its inherited patterns of behavior because it cannot reinforce them. They won't be gone, just faded. It will begin to trace new patterns that deal with the constraints of cage life. For the purposes of this example we'll say this chook's male. If you bred this suddenly caged male chook with a free ranging chook, and returned the free-ranger to rear the offspring free ranging, then some of the caged bird's offspring will have occasional pauses as their combined but contradictory instincts from both parents takes a moment to clarify the right response to whatever situation/stimuli has triggered recall of instinct, but overall they'll be normal and return easily, almost seamlessly, to the normal behavior of a free ranger.
If you bred this caged chook with another suddenly caged chook, however, the offspring would start to show lack of proper instinct. If you reared them caged, and bred them in turn, you would find even less normal instinct and possibly the start of negative misdirected instincts showing. Repeat this for a few more generations, then allow the results to free range, and they will not understand how to cope with the outside world. They'll gradually figure it out, especially if able to watch other chickens because many do learn from others by watching, but they won't be as smart as their free ranging bred and reared brethren. Instinctually, they have been retarded.
So, long story short, chickens can't retain unconfirmed instinct indefinitely, and it is easy to even accidentally modify or remove certain instincts from the gene pool/inheritance just by absence or presence of stimuli. But reclaiming the good instinct is much harder. Natural instincts need test subjects, over many generations, who tasted this and that plant and lived to tell the tale genetically. Otherwise each of your chickens have one fact from hundreds they need to have to be reliable in the unprotected environment.
One chicken knowing about the dangers of Oxalis and water that tastes like tin, which then breeds with a chicken knowing about the dangers of styrofoam and Morning Glory, won't save their offspring from spider lily, cane toad toxins, poisonous toadstools, toxic insects, etc. (Random examples). Chickens can be quite slow to learn which moths to leave alone, too. So it's somewhat dangerous to free range any chicken, but at least they're not as bad as cage bred chickens which might eat nails, foot-long grass, string, glass shards, washers, plastics, etc, as well as every toxic thing they find.
This also depends on where your chicken's most recent ancestors were raised. Free ranging in a suburban backyard or a carefully cultivated paddock gives them no instinct to deal with the varied plants, fungi, insects, and dangers inherent in forests, as an example. It might teach them to avoid otherwise healthy things, too because many insects in suburbia are poisoned, and so are many good plants. Chickens bred for many generations free-ranging in a place in the same country, but with different plants, won't have instincts about the right ones when shipped to your place. Instinct about location specific threats is of course restricted to location.
You'd have to take risks with cage bred chickens to get them back to functional free-ranger status. It's good to expose them gradually and in small amounts to different things for that reason. Mostly, chickens are very tough livestock and can take more abuse than most other livestock species. They enjoy their lives so much more if free ranging that I can't consider caging even if for their own relative safety. They'll die in the cage, too, but at least if they died outside it they enjoyed their lives.
The good news there is that chickens are rather like goats. They have powerful and large livers and can detox quite well. They tolerate a LOT of 'taste testing' of toxic things, and when allowed to exercise instincts (and if necessary, nursed through some mistakes), will become pretty clever about spitting out things that don't taste right. A chicken that's nearly died from eating the wrong thing obviously has an important bit of instinct to pass on, unless it was too stupid to remember. Some are, but not many.
They can also tolerate a lot of toxins that would kill any other livestock bird that I know of. So over a few generations they can quickly build up a heritable library of local knowledge to pass on to their descendants. Even cage-bred birds that are now free-ranging birds can, though they take longer. But in my experience, it's best to not assume any chicken from any background has the complete set of instincts. They can only be trusted with whatever their most recent ancestors were able to confirm is safe or unsafe. Sometimes they're too tough for their own good and need multiple illnesses or injuries before they realize what they've done wrong.
All the same it's always a good idea to have powdered charcoal in your possession, as well as olive oil or something to act as a rapid purge. Saves a lot of lives. It can even deal with some diseases. Best wishes.
