How old? Age makes a huge difference in guessing gender.
Right now, I'd guess the white bird and the wyandotte are female, based on a lack of male saddle feathers that the mystery chicken clearly shows.
The white one might be a zombie, or she could just be a mix of a dominant white breed and a non-fibro breed. It would help if we could get a picture of her head so we could see the comb.
The wyandotte is blue, not splash, but she's definitely a blue laced red wyandotte.
The mystery chicken might be a speckled Sussex, except it looks like his legs are yellow and Sussex have white legs. But he's definitely male.
View attachment 4243346
I've highlighted some of the male saddle feathers in red here