Clearing excess plant growth in bird enclosures reduces areas where rats may hide. In the process though, your grass gets trashed if you leave the job too late.
Grass takes a lot of punishment if you have waterfowl. Early autumn is a good time for reseeding, giving a few weeks of growth to get sward established. If you cannot exclude the birds from the area, you may be considering turf.
The cost of turf is 6 to 10 times that of seeding. What you are buying is time, but please, only lay turf which does NOT have plastic mesh embedded in it. When the supplier says ‘it disappears over time’ what they mean is the grass hides it. The mesh, though fine, is tough and can easily entangle birds.