housing /compound building

Question
i have 8 guinea's i want to make a home like compound with plants and pond it is around 6 meters long and 2 meter wide fully enclosed
1  can i keep birds with them flying and walking
2  will they eat the eggs
3  what ornamental plants can i use not worried about them  eating them, just if any particular one will harm them egg  New Zealand grasses non-spiky cactuses
4  will they breed and care in a community site when a male is introduced temporally to service multi sow's then removed to leave sow's to do their part together
5  what is coming close to over-crowding in space stated with walk-in height, full mesh walls, ample air flow closed in sleeping bay

thanks on behave of my family

Answer
i actually made a very similar setting, just without the birds though I did come close to getting some.

a lot of the gunea pig community are against these types of set ups, I honestly think it is because they do not fully understand it, personally i think it is a brilliant thing and is great for the guinea pigs.

bascially what you want is an avairy . the bigger the avairy then the better, as for actual size in relation to guinea pig to space ratio i would recommend seven foot squared per pig, you  could squeeze this down to about 5ft per pig but honestly if you're having a living floor with grass and plants and things then it will become a muddy poo pit which will be unslightly and bad for guinea pigs.

plant wise the easiest thing to do is to select fruit bushes and grasses, the cacti should be fine if they are edible which you can google, though the guinea pigs might chew them to bits.

on the matter of chewing you are better off picking bushes because guinea pigs will only eat the first half foot of vegitation, after that first half foot the plant will be safe (they wont eat the wood and bark) anything smaller than that though will be eaten, your grasses can be eaten but will likely be eaten all the way down to the roots.

bird wise, if you stay along the lines of button quail, tits, bugee and finches then you should be fine, avoid parrots and parakeets etc, if they have been known to nip at humans then they have been known to nip at other animals.

as for the button quail they should be fine, providing they are not rearing young or nesting, then they might become agressive, also i dont know how the male quail would feel about guinea pigs entering there territory.

avoid chickens ducks, larger quail breeds and geese, you are asking for trouble.

final thing as for intrpducing a male for breeding just watch out, your numbers will grow insanly fast, you would be better off removing a female to place with a male for a fortnight to keep the breeding under control, the other females would help look after the young as well if you were to have a neutered male then he would also help look after them. in fact i would consider a neutered male in that setup anyway, herds tend to work better with a male keeping the peace.

all the best