Have 2x13 week Australorps, Can I add wyandotte to flock?

[Fowl_language]

I have two 13 week Australorps and ive also got two Isa browns simillar age on the way.

My question is, can I add a 15 month old Wyandotte Bantam to the flock or will there be fighting?

Also my Australorps are not flighty at all, very happy with the run they have, are the wyandottes likely to fly the coop?

Cheers,
Liam.

 

[Fowl_language]

Also the area is 25m squared so 269square feet, is that big enough for 4 hens and one bantam?