There are 300+200+80 = <<300+200+80=580>>580 birds in total
Every day 20+8+5 = <<20+8+5=33>>33 birds are lost
After a week which is 7 days, 33*7 = <<33*7=231>>231 birds would be lost
There would be 580-231 = <<580-231=349>>349 birds left in the poultry
#### 349