**1. 88 hens, 2 parrots, 10 roosters (88+2+10=100, 22+8+70=100)
2. 84 hens, 11 parrots, 5 roosters (84+11+5=100, 21+44+35=100)**

x- hen,

y- parrot,

z- rooster

1) x+y+z=100

2) 0.25x+ 4y+ 7z=100-->x+16y+28z=400

if subtract 1) from 2) we get 15y+27x=300-->5y+9z=100,

we get 2 answers: y=2, z=10, then x=88 or y=11, z=5 and x=84